Mach 1 Club

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While there have been some considerable advances in engine-building technology over the past 30 years, one of the most important lessons we can learn is that it’s the small details that can make or break an engine-building project. The two most important details are checking clearances and triple-checking your work. Far too many of us are not attentive enough to detail, and we learn some hard and expensive lessons — when an overlooked rod bolt fails half way down the track, or when a carelessly seated valve keeper escapes at high revs, destroying the piston and cylinder wall below in less than a second. These are the kinds of important details we don’t want you to miss during your budget engine build.

Lack of proper planning is another reason for the demise of many an engine project. Wise planning is the most important tool you should use in your project. Before heading off to the speed shop, ask yourself the all-important question, “What do I want from this engine?”, then do the plan.

Part of doing the plan is knowing exactly what you can afford, then not giving in to ego and the temptation to spend more than you have. That’s the mistake many of us make along the way. We tend to want to impress our peers, the machine shop, and especially the significant other, but these are the wrong reasons to build an engine. Don’t build an engine to impress anyone besides yourself because you’re the one who has to live with the result. If you’ve overspent, then you can count on grief when it’s time to pay the monthly bills. This is why we stress staying within your budget.

Most of us overbuild our engines. We build more engine than our Ford needs, which costs unnecessary time and money. For example, if you’re building a 1965 Mustang and you want it to be the fastest thing around, your first thought might be to build a 351W stroker that displaces 427ci. Future plans include fuel injection and a supercharger. Just imagine, the power of a big block in a lightweight stallion, but is it more than your Mustang (and your driving skills) can handle? You don’t have to worry about impressing us. We’ve been there, too, and we understand the drawbacks of overbuilding. This is why we’re sharing the cold, hard facts of engine building with you — so you don’t make the same mistakes.

Too many enthusiasts build more engine than a car can safely handle. When we infuse big-block displacement power into a lightweight Mustang, Falcon, or Fairlane, we’re not thinking about the engine and vehicle as a package. Most of us get it backwards. We build a powerful engine, then we wonder how to manage all that power safely. It is better to build the car first, then the engine, because too much power in an unprepared platform can get you maimed or killed. A well-thought-out platform will have good brakes, a handling package, traction enhancement, the right tires and wheels, a rear axle that can take the punishment, and a mature driver who understands all of this.

The goal of this book is to teach you how to build a reliable, affordable engine that will make the power you need. No matter the formula, one basic principle is constant: Performance level is tied directly to budget. The greater the budget and know-how, the faster you will go.
You are not going to make a 600-horsepower small block for $2,500. However, you can build a healthy 350-horsepower small block for approximately $2,500 to $3,000 that will serve you reliably. Keep your expectations and planning realistic. Then go work your plan with perseverance.


Before you even start to plan, you must decide what you can reasonably spend on your build. Believe it or not, if you do your homework and learn how to do much of the work yourself,
you can get into a fresh engine for approximately $2,500. Even if you have never done it before, building an engine is not difficult if you pay close attention to detail. Engine assembly is costly if
you farm it out. Machine work is also expensive, but most of us don’t have the necessary equipment or the know-how to do it ourselves. Engine assembly boils down to having the right tools and a super clean shop environment. Certain tools, like the torque wrench, piston ring compressor, micrometer, and dial indicator, can be rented locally. You will only need these items for a weekend, which makes them affordable.


When you’re new to the world of engines, it is easy to get carried away in the tool department. After all, we need all those things to get the job done, right? That first trip to Sears is often like a first trip to the speed shop. You lay down the credit card and come home with a wealth of goodies, but they don’t always apply to building an effective engine.

We suggest Sears Craftsman tools because they have a lifetime warranty, great reputation, and there’s a Sears store in nearly every area of the world. The Craftsman warranty is written with no nonsense and no fine print. Bust a socket and Sears will replace it with no questions asked. Strip out a ratchet and Sears will hand you a new one or rebuild your old one. Sears Craftsman tools are the best tool value going. The next best tool value is Husky in the “bang for the buck” department. You can find Husky tools at many home improvement or hardware stores for even less than Craftsman, yet with the same no nonsense lifetime warranty.

Our Beginner’s Tool Shopping List is intended to get you started and will last you the rest of your life with care. It is even something you can pass along because, with proper care, it will last several lifetimes. Most of us buy socket sets, but we forget to go for the deep-well sockets, which you will need in the course of an engine build. One other thing to keep in mind, opt for 6-point sockets, not 12-point. A 6-point socket won’t strip a bolt head and provides a firm grip. Make sure your socket sets have at least two extensions — one 3-inch and one 7-inch. Spring for the universal adapter as well for easy access. If you can afford it, buy a matching set of 12-point shallow and deep-well sockets because they do have a purpose with some engine applications.
When you’re shopping for screwdrivers, hold one in your hand first. You want a screwdriver that feels good in your hand and offers adequate grip comfort and mechanical advantage. If your hand slips around the handle, then it is a poor design. The tip should be super tough steel that will not strip out or break. Go the extra mile and invest wisely now in a screwdriver that will last you a lifetime. Another idea is to buy screwdrivers with bright orange handles for visibility and safety. This lessens the chance of leaving tools where they don’t belong.

We push the idea of quality tools because there really is a difference. Inexpensive wrench sets you can buy for around $10 won’t get the job done effectively. A low-quality forged or casting will strip out and leave you hanging on a Sunday afternoon when you need it most. With Sears Craftsman (and this is not a commercial endorsement), Husky, MAC, or Snap-On tools, you get a lifetime warranty that’s good for as long as the tool exists — for you, your child, your grandchild, great grandchild, and more. MAC and Snap-On tools tend to be very expensive and available only off a truck at better garages everywhere, which makes Craftsman and Husky a better value and easier to find.

Proper tool care once you’ve made the investment is what assures you reliability in the future. Keep your tools clean and serviceable. Lubricate ratchets periodically with engine oil or white grease for best results. Drill bits should be sharpened periodically. When you’re using a drill, run the bit slow and keep it wet with lubrication while drilling. Drill bits begin to squeak whenever they’re dull. Invest in a drill-bit sharpener or find a reliable shop that sharpens drill bits. Most shops that sharpen lawnmower blades and chain saws can sharpen your bits.

It’s also important to know when it’s time to retire tools. Tools that are not serviceable can be dangerous. A loose hammer head, for example, could rearrange yours or someone else’s dental work — or break a window. Cracked sockets, worn wrenches, busted screwdriver handles, stripped ratchets, and other forms of serious tool deterioration are reasons to invest in fresh equipment. It is about your safety and the integrity of your work.


There are many tools you will only use during an engine build that are expensive. It may be more cost-efficient for you to rent these items. Most shops make rental tools available. Look for the “multi-purpose” in any tool you’re thinking about renting. If you expect to use the tool again, it may well be worth the investment to purchase it now. When renting tools, rent only at the time you intend to use them. Don’t rent every tool mentioned here at the same time because you’re not going to use all of them at the same time.

When renting torque wrenches, keep in mind they are typically either beam or breakaway types. We suggest the breakaway type that “clicks” when the specified torque is reached. Be sure to learn how to properly use a breakaway torque wrench. Ask for instructions when you rent the tool. Keep in mind two things: First, never use a torque wrench to remove a bolt or nut, as you will disturb the calibration. Second, never overtorque a fastener. When you torque a fastener, you are stretching the bolt stock. Too much torque and you stress the fastener. Specified torque readings are there to ensure fastener integrity.

Piston ring compressors are available in different forms. The most common type available to rent is an adjustable type. There is also a ratcheting type that makes piston installation a snap. Custom-sized billet ring compressors are costly and not for the novice.

Harmonic balancer pullers are a borderline rental item. This is something you may use again and again. They don’t cost that much to buy, which is what makes them a borderline item. Balancer pullers also make great steering wheel pullers.

There are two basic types of valve spring compressors -- one you use in the shop on a head in the raw (looks like a huge C-clamp) and one you use with the head installed (more like a pry bar used only for ball/stud fulcrum rocker arm applications). For engine rebuilding, you’re going to need the C-clamp type. You can sometimes pick these up at a discount house for less than it would cost to rent one for several days.

Freeze plug and seal drivers are one of those borderline items you could use again and again. You an also use a like-sized socket as a driver on the end of an extension. This saves money, but could damage the socket. Don’t be a tool abuser.

Thread chasers are a vital part of any engine build because you want clean threads. Clean threads yield an accurate torque reading when it’s time to reassemble the engine. Thread chasing should be performed when the block returns from the machine shop clean, machined, and ready for assembly. Machine shops that are on the ball will have already chased your threads. However, thread chasing is time consuming and machine shops don’t generally do this unless asked and paid for the service. If you do it yourself, it’s a good idea to chase every bolt hole. When a thread chaser is outside of your budget, use Grade 8 bolts and other fasteners with WD-40 to chase the threads. This may sound crude, but it will save you money and get the job done.

Engine stands are one of those purchase/rent questions because renting can sometimes cost you more than simply buying. Harbor Freight Salvage has some of the best values going at $50 to $100 for a stand. If you’re building a heavy big block, don’t cut corners here. Invest in a four-legged engine stand for stability and safety. The low-buck $50 stand will not hold up under the weight of a 650-pound big block. You don’t even want to think about what happens when an engine stand fails — it’s sudden, noisy, and destructive.

The decision to rent or buy tools boils down to how often you will use the tool and how long you will need the tool during your engine build. Any time you’re going to need the tool longer than 1 - 3 days, you’re probably better off buying. If you have to buy, look on the bright side. You can always loan it to friends or sell it after your engine is finished. Keeping it makes it a useful piece of community property among friends.


We cannot stress enough the importance of keeping a clean, organized shop. Do your engine teardown work where you can catalog everything and keep it in its rightful place. Keep engine parts and fasteners in jars or plastic containers that are labeled. Haul the block, heads, crankshaft, and connecting rods to a machine shop immediately upon disassembly. This avoids any confusion and keeps you rolling. If you cannot afford the machine shop at the time, leave the engine assembled until you are ready. We speak from experience on this one because too much is lost both mentally and physically once the engine is disassembled. Keep disassembling, cleaning, machine work, and assembly as cohesive as possible.
It is always a good idea to keep an engine project organized from planning to completion. Know what you’re going to do and when you’re going to do it. Then get busy and see your engine project through to completion. Nothing is more discouraging than a disassembled engine that’s going nowhere because you didn’t have a plan.

Making Power

There is plenty of folklore about making power, such as the myth that it’s easier to make power with a Chevrolet than with a Ford. Nonsense. The truth is, you can make just as much power with a Ford, for the same amount of money, that you can with a Chevrolet. There is no black magic here — just the simple physics of taking thermal expansion and turning it into rotary motion.
To learn how to make power with a given engine, we have to understand how power is made. How much power an engine makes depends on how much air and fuel we can pump through the engine, and on what we do with that fuel and air mixture during the split second it is in the combustion chambers.

We have to think of an internal combustion engine as an air pump. The more air and fuel we can pump through the cylinders, the more power we’re going to make. This is why racers use big carburetors, manifolds, heads, superchargers, turbochargers, and nitrous oxide. Racers understand this air pump theory and practice it with wreckless abandon, sometimes with catastrophic results. Good racers also understand the “too much of a good thing” theory. Sometimes it can cost you a race, and sometimes it can cost you an engine.

Getting power from our air pump takes getting liberal amounts of air and fuel into the chambers, then squeezing the mixture as hard as we can without damaging the engine. When we raise compression, we increase the power of our mixture yields. It is the intense heat of compression coupled with the ignition system spark that yields the energy from our mixture. The more compression we have, the greater the heat created to ignite the mixture.

However, when there’s too much compression and with the resulting heat, the air/fuel mixture can ignite prematurely resulting in preignition and detonation. So we have to achieve the right compression ratio to get the most from the fuel we have. Today’s street fuels won’t tolerate much over 10.5:1 compression. This means we have to look elsewhere for answers in the power equation, like more aggressive camshaft profiles, better heads, port work, hotter ignition systems, exhaust headers that breathe better, state-of-the-art intake manifolds and carburetors, even electronic-fuel injection where we never thought of using it before.

The thing to remember about gasoline engines is this: The fuel/air mixture does not explode in the combustion chambers, it “lights off” just like your gas furnace or water heater. Because the mixture is compressed and ignited, it lights off more rapidly. Combustion in a piston engine is just that, a quick fire that sends a flame front across the top of the piston. Under ideal circumstances, the flame front will travel smoothly across the piston dome, yielding heat and pressure that act on the piston and rod to yield rotary motion at the crankshaft. A bad “light off” that originates at two opposing points in the chamber is the preignition or detonation that we mentioned earlier. The opposing light offs collide creating a shock that hammers the piston dome which is the pinging or spark knock we hear under acceleration. The objective is to get a smooth, quick fire, with the flame front traveling in one, smooth direction for maximum power. Call this power management.

Power management is having the right balance of ignition timing, fuel mixture, compression ratio, valve timing events, and even external forces like blower boost or nitrous input. All of these elements have to work together if we’re to make productive power. Let’s talk about some of the elements we need to make power.

Nitrous oxide or “squeeze” is all the rave today for those looking for quick and easy power (50 to 150 horsepower) on demand. Nitrous makes boatloads of power at the touch of a button, but it can be very harmful to a budget engine that isn’t properly prepared. Nitrous will severely damage your pistons and rings if not properly executed. It can and does hammer rod bearings resulting in severe wear. It is also hard on main bearings due to these loads. No matter what the nitrous oxide optimist club will tell you about “laughing gas”, nitrous can and does shorten engine life. So don’t be drawn into believing it’s a magic horsepower pill without consequences. If you’re going to be using nitrous oxide, be prepared for its shortcomings. Accept the fact that nitrous will shorten engine life no matter how it is used. The more aggressively you use nitrous, the shorter your engine will live.

It is easy to be lulled into believing a larger carburetor, more aggressive camshaft, and large port heads will make more power but this isn’t always true, especially in budget street engines. Induction, camshaft, and heads should always jibe with your performance mission. What’s more, you want your engine to survive while making all that power. Your engine build plan needs to include a common sense approach that involves the right selection and packaging of parts for best results.

If you’re building a daily driver, you’re going to have to compromise to some degree in terms of performance if you want reliability. We compromise because radical engines don’t do well for the daily commute. They also struggle to pass a smog check, depending on where you live. Radical camshaft profiles give the engine a rough idle, which can be frustrating in traffic and make it virtually impossible to pass a smog check. Loud mufflers can cause hearing damage and make for an annoying drive. They can also get you a ticket for noise pollution in some communities. A high compression ratio can cause overheating when traffic comes to a stop. Overcarburetion fouls spark plugs and pollutes the air.

This brings us to another valid point -- air pollution. Environmentalists and performance enthusiasts don’t get along, but it is our responsibility as performance buffs to build and tune our engines for cleaner emissions and better human health. This doesn’t mean you have to go out and buy catalytic converters and a smog pump. It does mean you need to package your induction and ignition systems for optimum emissions performance at the tail pipe. In short, clean up your performance act.

Carburetors play a role in pollution, too. A big, fat 750 or 850cfm Holley carburetor looks good at the drag strip, cruising spot and car show, but it is not a practical carburetor for everyday street use where clean emissions are important. This isn’t so much about Holley carburetors as it is about carburetor sizing in general. We want carburetor size and engine mission to be compatible for optimum performance and cleaner emissions.

If you think this clean emissions hoopla is a lot of nonsense, consider the last time you were behind a hopped up vintage musclecar in traffic that made your eyes water. Also remember that if your vehicle falls under the guidelines of state emission laws and smog checks, the law doesn’t give you a choice. Clean up your exhaust emissions or face revocation of your license plates in some states.

Building an environmentally responsible engine doesn’t have to be difficult either. Carbureted engines are not going to burn as clean as fuel-injected versions. If you can run electronic fuel injection, do so for cleaner air. Do so for your own health and for the sake of others who breathe. If you can’t, be conservative in your performance plan and dial in the right size carburetor.
Instead of a 750 or 850cfm carburetor, opt for a 600 or 650cfm carb and see how your engine performs. A carburetor that’s too small will become apparent quickly in the absence of torque as RPMs increase. Large carburetors give us more torque on the high end. Smaller carburetors do well on the low end. Choosing the right amount of carburetion is often trial and error.

Keep proper carburetor jetting in mind, too. Jets that are too large will make the engine run rich or “fat”, burning the eyes of those who have to follow you. Jets that are too small can be harmful if you’re leaning on it hard and lean detonation burns a hole in a piston. Again, fine tune carburetor and jet sizing for best results. Always err on the side of rich versus lean for longer engine life. If you really want to make a lasting impression on the community, go for a smog check each time you make a carb/jet change and see what it does for emissions. Cleaner air is up to all of us.


The important question is, how much power do you want your engine to make and what can you afford? We’re assuming you have invested wisely in your engine’s bottom end with healthy parts and building procedures that will make the most of the engine’s potential. For example, if your plan is 450 to 500 horsepower from a small block, stock rods and cast pistons won’t cut it. Ask yourself what your engine’s bottom end can withstand, and then program the power accordingly. If you are seeking 450 horsepower, then hopefully you have prepared the bottom end with heavy-duty rods and pistons, coupled with building techniques to ensure that your engine survives.

Making power in a Ford engine has everything to do with air flow. A popular misconception suggests that the larger the carburetor, intake, and cylinder head ports, the more power you are going to make. In part, this is true. However, you must ask, where do you want the engine to make power and why? If you are building a drag or circle-track racer, you are going to want the engine to behave differently than you would a street engine. Racing engines make their power in a much higher RPM range than a street engine. A circle-track racing engine is going to make power differently than a drag-racing engine. Torque needs to come on strong from part throttle to full throttle with a circle-track engine. Drag-racing engines need to make torque at high revs. In either case, we have to design an engine that delivers power when it’s needed or the whole thing is pointless.

Have you invested in a strong bottom end? Before you can make real power, you should have a bottom end that can handle the power. All that power is useless if you have a soft bottom end. Failure should never be an option.

A good street engine should make excellent low-end torque, yet be snappy when it’s time to wind it tight. With that in mind, which carb, manifold, cylinder heads, and camshaft should you choose? First, you’re going to want cylinder heads that are compatible with your pistons. With flat-top pistons (which most street engines should have), the field is wide open. If you’re opting for stock cylinder heads, keep combustion chamber size and deck thickness in mind. Nothing beats older Ford cylinder heads for compression, thanks to smaller chambers. An early 289/302 small-block cylinder head with 57cc chambers, coupled with flat-top pistons, will yield a compression ratio of approximately 10.0:1 depending upon compression height. Late-model 302 heads with 64cc chambers will yield less compression, which may mandate shaving the block and head deck surfaces to achieve the 10.0:1 ratio desired. Keep this in mind when shopping cylinder heads.

Making power has everything to do with airflow. Where do you want your engine to make power? Where will your engine’s power band be most of the time? Large ports, such as those found in this 351C-4V head, have little value in daily street use. Huge ports do their best work at high RPM, where we need lots of airflow. For low-end torque, we need smaller ports where air velocity increases at lower revs, giving us all-important torque where we need it most.

Cylinder Block

The foundation for an engine build is the cylinder block. Whether it’s a small or big block, selecting the proper block for your build is the single greatest decision you will make aside from choosing the right machine shop. Depending on the block you need, selecting the right one can often be a great challenge. For example, a four-bolt main Boss 302 block will be a lot tougher to find than a garden-variety 302 block. Likewise, a 427 cross bolt will be more of a challenge to locate than a 390 block. In this section, we’re going to show you how to choose a block. We’re also going to show you how to tear down, inspect, and build one.

When you’re shopping for a block, close inspection is vital. The cylinder bores should be sized before you go any further. Small-block Fords should never be bored beyond .040-in. oversize. Some builders have gone to .060-in. oversize, but this is not recommended. If a block is already at .030-in. oversize, you may have .010 in. more to play with. If bore taper is greater than an .011-in. variance, find another block because the only overbore choice then is .060-in. oversize. Three exceptions to the small-block overbore limit are the 351C, 351M, and 400M. These blocks can be bored to .060-in. oversize if they have already been bored .030-in. or .040-in. Big blocks, with the exception being the FE-series 427, can be bored to .060" oversize. The 427’s limit is .030" oversize, and this is marginal.

While you’re shopping for blocks, we suggest having the block sonic tested for cracking and other irregularities. Sonic testing finds irregularities in the casting the human eye cannot see. Some Ford blocks, such as the 351C, 351M, and 400M, are notorious for cracking. Cracking is hard to see even with an antiseptic casting. Sonic testing can be expensive, but it beats the costly mistake of cleaning and machining a block only to discover it is cracked later.


Your initial block inspection should reveal obvious defects like cracks, damaged threads, damage to the cast iron or aluminum, scratched or gouged lifter and cylinder bores, flawed decks, welds in the casting, chipped or broken cylinder skirts, etc. Close inspection is important before working your plan.

Some block cracking can be repaired via welding or JB Weld. JB Weld is a two-part catalyzed product that works well with cracked cast iron. Properly mixed and cured, it will last the life of any engine block. For JB Weld to work effectively, you need a clean surface and a crack that has been carefully stop drilled at each end. Just a small 1/16-inch stop drill hole at each end slows and stops cracking. Then weld or JB Weld the crack. We suggest against the use of JB Weld on the cylinder walls and decks where stresses can be extreme. Your machine shop will know best on what call to make on repair. Some blocks are cracked beyond repair.

When you’re putting together a good formula for a block, sometimes you have to opt for different main caps for a stronger build. For example, you can take the main bearing caps from a 289 High Performance block that is beyond salvage and use them on a standard 289/302 block. You can also use main bearing caps from a Mexican block 289/302 for the same purpose because they’re wider and heavier. Along this same thought is the 351C block. You can convert a 351C two-bolt main block to four-bolt mains so long as you have four-bolt main caps from a trashed four-bolt main block. We do this by drilling and tapping the two-bolt main block for four-bolt mains. In the raw, the two-bolt and four-bolt main 351C blocks are basically the same casting.

Main bearing saddle trueness is another important issue facing the budget engine builder. The alignment of the main bearing saddles is rarely a cause for concern during an engine rebuild. Align boring and honing the main bearing saddles can be expensive. But it’s sound judgment. It would be wise for you to have a machine shop check the line bore for proper alignment before going any further. If the block needs to be align bored and honed, it is well worth the cost in terms of increased engine life because it gives the crankshaft a true foundation. Distorted main bearing saddle alignment puts undue stress on the crankshaft, which directly affects wear and tear. The stressed crankshaft alters connecting rod side clearances and puts stress on the main bearings. This can result in shortened engine life due to abnormal wear patterns.

With bore size and line bore out of the way, it is a good idea to check the block for cracks, obstructed water jackets and oil galleries, and other problems. Like we said earlier, cracking is something you don’t want to find after the machine work is finished or the engine is assembled. Finding it early in the game is crucial. Magnafluxing and sonic testing are two means of checking for cracks. Magnafluxing is a simple test easily accomplished by a machine shop. We set up a magnetic field around the suspected area using an electromagnet, then we sprinkle iron powder over the area. Iron particles will collect at the crack, making it easy to see.

Spot checking is yet another means of crack detection. With spot checking, we use a dye and a powder developer to “spot check” cracks. The nice thing about spot checking is the ability to use it on aluminum castings as well as iron. Magnafluxing cannot be used on aluminum castings.

The most common cracking areas are block decks and main bearing webs because these areas are subject to high stress. Check these areas closely and take your time. Block decks become stressed from cylinder head bolt torque plus the high heat and pressure that take place in this area. Main bearing webs are also placed under great stress from bolt/stud torque, plus the horrific loads this area experiences. Use every means available to ensure you’ve found a solid block.

Obstructed coolant passages have created more than their share of headaches for engine builders. Mass engine rebuilders are sometimes guilty of knocking old freeze plugs into the water jackets to speed disassembly. Unfortunately, whoever gets this engine after the fact must deal with overheating issues because those freeze plugs knocked into the jacket obstruct coolant flow and heat dissipation. During disassembly, take a bright light and inspect cooling passages (water jackets) for any obstructions and corrosion. Passages between the heads and block sometimes become clogged with rust and iron particles. Make sure these passages are clear.

Oil galleries can become clogged with sludge, metal particles, and nylon, which starves important moving parts of oil. We mention “nylon” because failed timing sets shed nylon and aluminum particles into the oil pan clogging the pick-up and oil galleries. What’s more, these particles find their way to the main, rod, and cam bearings causing excessive journal wear and engine failure. This is why close inspection of oil galleries is vital to any engine build. You’re going to need a long wire brush, solvent, and water under pressure to ensure all passages are sanitary. If this seems excessive, consider the cost of engine failure and having to do this all over again.

Another area we rarely see addressed is lifter bores, but lifter bore side clearances are vital to oil control and proper lifter function. Lifter bores should be inspected for scratches and nicks, then honed as necessary. Engines that have been sitting for a long time often experience ceased lifters that become welded to the bores. We suggest extreme caution removing the lifters because you can permanently damage the bores. Then inspect the lifter bore for scoring, nicks, and other damage. Ceased lifters can be worked loose with WD-40 (a good soaking) and a pair of vice grips. Lifter bore side clearances should be checked using a new lifter as a reference. Side clearances should be 0.0005 to 0.0020". You may also use a small dial-bore gauge or micrometer to check lifter bore size. Check the bore diameter, then lifter diameter to determine clearance. Remember, all lifter bores should be checked because all wear differently.


Ford makes it easy for enthusiasts to identify corporate castings. Please understand that Ford casting numbers aren’t always the same as part or engineering numbers. Identifying a casting is a matter of knowing what Ford part and casting numbers mean. Here’s what you can expect to see.

It’s easy to identify Ford castings once you understand the system because there’s not only a casting number, but a casting date code that tells you exactly when the piece was cast. Not only that, a date code is stamped in the piece which tells the date of manufacture. With these two date codes, we know when the piece was cast and when it was ultimately manufactured.

Ford part numbers can be found in the Ford Master Parts Catalog on microfilm at your Ford dealer or in one of those 900-pound parts catalogs from the good old days. Because Ford has discontinued a great many parts for vintage Fords, these part numbers don’t always exist in present day dealer micro films. This is called “NR” or “not replaced” which means it isn’t available from Ford any longer. However, casting numbers on parts tell us a lot about the piece.


Date codes can be found two ways in Ford castings. When the four-character date code is cast into the piece, this indicates when the piece was cast at the foundry. When it is stamped into the piece, this indicates the date of manufacture.

Another area of interest to Ford buffs is where the piece was cast or forged. With Ford engines, we’ve seen three foundry identification marks. A “C” circled around an “F” indicates the Cleveland Iron Foundry. “DIF” indicates Dearborn Iron Foundry. “WF” or “WIF” indicates Windsor Iron Foundry. Single and double-digit numbers typically indicate cavity numbers in the mold.

Rotating Assembly

What we build into an engine’s bottom end directly determines durability and lifespan. Believe it or not, you can build integrity into a budget engine if you understand what counts and where to prioritize. Your focus needs to be on areas that do count. This means using the best parts available in your budget range; in short, spending money where it makes the most sense in a budget engine build.

When we’re planning a budget engine, it is wise to plan for the best our budget can buy, then cost down as necessary, prioritizing as we go. For example, you might want a set of Crower Sportsman rods topped with forged pistons. When cost enters the picture, you may have to throttle back to hypereutectic pistons and modified stock rods to get the job done. Compromising down under is something you do carefully, answering yourself honestly what this engine is going to be.

Before you get started, it is important to remember there are no guarantees when we build an engine. Anytime we build an engine, we always run the risk of engine failure due to flawed materials or faulty assembly procedures employed during the build. Additionally, there is the risk of engine failure due to abuse once in service — such as over-revving, poor tuning, or the neglect of proper maintenance like regular oil changes. The best we can do is to put quality into an engine build in the first place, then do our best to treat the mill respectfully once the chambers are warm.

Treating the mill respectfully means using common sense. Never push a cold engine, for example. Cold oil doesn’t flow and coat moving parts as liberally as warm oil. Cold parts need warm-up time to expand to proper tolerances. Operating an engine in a poor state of tune is another factor. Too much timing or a lean fuel mixture is hard on an engine. Too much of either will destroy an otherwise healthy engine in seconds.


Before we get into how to build a solid bottom end, we must first talk about
balancing issues and how they pertain to Ford V-8 engines. Proper dynamic balancing is rooted in having the right combination of rotating and reciprocating parts. All Ford small-block engines, including the 351C, 351M, and 400M, are “externally” balanced. This means we counterweight the engine “externally” on the flywheel/flexplate and harmonic balancer to achieve dynamic balance.

Why go outside and externally balance? Because the crankshaft counterweights inside don’t always give us sufficient weight to counter reciprocating bobweight (rods and pistons). We add counterweight to the flywheel and harmonic balancer to make up for the difference in reciprocating weight inside the block. Look at a small-block Ford flywheel, flexplate, and harmonic balancer and you can see the counterweighting. On flexplates, the counterweight is welded on. With flywheels, it’s an integral part of the casting. Holes are drilled in the flywheel, often opposite the counterweight, to achieve ideal dynamic balancing. The same can be said for the harmonic balancer, which is also drilled to achieve ideal dynamic balance. We drill flywheels and harmonic balancers to remove weight where it isn’t needed.

One Ford small block, the 1963-67 289 High Performance V-8, uses additional counterweighting (a slide-on counterweight) at the front of the crankshaft to allow for heavier reciprocating weight inside. If you’re building a replica Hi-Po, you don’t have to have this counterweight. Your machine shop can fill the crankshaft counterweights with Mallory metal or add weight to the flywheel/flexplate.

Why is all this balancing hoopla important? Whenever we’re dynamic balancing an externally balanced engine, we must have the flywheel (manual transmission), flexplate (automatic transmission), and harmonic balancer present at the time of balancing. Horrible vibrations abound when we ignore this fact.

What makes the small-block “external” balance issue more complicated is 28-ounce offset balance versus 50-ounce offset. Earlier Ford small blocks like the 221, 260, 289, and 302 V-8s through 1981 were 28-ounce offset balanced. When Ford began producing the 5.0L (302) High Output V-8 in 1982, a 50-ounce offset balance was used to allow for heavier reciprocating masses inside. Small-block crankshaft flanges are drilled to allow flexplate or flywheel installation one way only. This prevents us from incorrectly installing the flywheel or flexplate, adversely affecting balance.

Ford FE big-blocks were both internally and externally balanced depending on engine type. All FE engines, except the 410 and 428, were internally balanced. Internally balanced means the crank, rods, and pistons are balanced together without concern for the flywheel, flexplate, or harmonic balancer. Internal balancing means there’s enough counterweighting in the crankshaft counterweights to do the job without help from the flywheel, flexplate, or harmonic balancer.
The 410 and 428 were externally balanced because they had greater reciprocating weight than other FE counterparts. Both had heavier rods and pistons, which made it necessary to add counterweighting outside the engine at the flywheel, flexplate, and harmonic balancer. The 428 Cobra Jet has an additional slip-on counterweight at the front of the crankshaft behind the harmonic balancer to allow for heavier moving parts inside.

We’ll take the FE story a step further with the FT (Ford Truck) big-block cousin. If you’re using a cast or steel-forged FT truck crankshaft (affordable brute strength) in your FE engine, always remember FT engines are externally balanced which means the flywheel, flexplate, and harmonic balancer must be included in the balancing process.

All 385-series 429 and 460ci engines are “internally” balanced, which means they don’t need any help outside at the flywheel, flexplate, or harmonic balancer. This is a big plus for the 385 because it makes dynamic balancing easy. When it’s time to replace a clutch and flywheel, you can expect a good balancing experience because the crankshaft, rods, and pistons are independent from the flywheel, flexplate, and harmonic balancer.


Pumping up the displacement in your Ford V-8 doesn’t have to be expensive. In fact, when you opt for a cast crankshaft and cast pistons, stroking your budget engine doesn’t have to cost any more than a simple rebuild. Stroker kits are available from Performance Automotive Warehouse (PAW) for not much more than a budget engine kit. Ditto for Summit Racing Equipment and Ford Racing Technology.

An engine is stroked by increasing the distance the piston travels in the cylinder bore. When we increase the distance the piston travels in the bore, the bore takes on more air and fuel resulting in more power. Stroker kits vary in scope and cost. Often you can stroke an engine without buying a kit using off-the-shelf parts. For example, you can stroke a 390 to 410+ci by installing a 428 crankshaft, or turn a 429 into a 460 with a 460 crankshaft. Just offset grind a 302 or 351 crank and use the right rod and piston for increased displacement from your small block.
Stroker kits are the easiest means to displacement when off-the-shelf Ford parts won’t get you there. Ford Racing, for example, offers a 347ci stroker kit (M-6013-B347) for 289/302 blocks. This kit sports a nodular-iron 3.40" stroke crankshaft, KB flattop pistons, Federal Mogul high-performance connecting rods, and Grant piston rings. You must provide all machine work and dynamic balancing. Remember, this is an externally-balanced engine. Flywheel, flexplate, and harmonic balancer must be present for balancing.

Ford Racing also offers a 514ci stroker kit (M-6013-A514) for 429/460 big blocks. This kit includes a nodular-iron crankshaft with 4.30" stroke, M-6200-A514 connecting rods, choice of TRW forged pistons, Speed Pro piston rings, and Federal Mogul bearings. Like the small-block stroker kit mentioned earlier, this kit requires externally balancing with flywheel, flexplate, and harmonic balancer present.

Stroker engines are also available from Ford Racing. You can install 600 horsepower in a weekend with the M-6007-B514 crate 514ci big-block package. This engine has been dyno tested at 600 horsepower at 6,250 rpm, which is 590 ft./lbs. of torque at 4,750 rpm.
Coast High Performance has a variety of stroker kits for Ford V-8s. The most popular is the 347ci Street Fighter small block. Several versions with either I-beam or H-beam rods are available for your application depending on budget. Coast also offers 377, 408, and 426ci stroker kits for 351W and 351C engines. If you’re building a 385-series big block, Coast can help with 501, 514, and 557ci stroker kits for your monster big block.

Keep in mind that when you’re ordering a stroker kit for your Ford V-8, the more expensive kits sport H-beam rods, forged pistons, and steel cranks. Rules of budgetary concern must apply here. Street engines don’t need race-ready pieces. Keep your expectations realistic and an eye on the check book.

Cylinder Heads

You can achieve significant gains in engine power with the proper selection and modification of cylinder heads. Cylinder head port size and shape, coupled with combustion chamber size and shape, determine an engine’s power personality. The “bigger is better” theory most of us have accepted over the years doesn’t always work to an engine’s advantage. A street engine can have too much cylinder head, which adversely affects driveability. The same can be said for racing engines, depending upon the application. Ports that are too large hurt the low-end torque we need for effective street performance. Your challenge is to achieve the right combination of port size and camshaft profile to enhance driving pleasure. You’re going to want a cylinder head/piston/induction/camshaft combination that will serve you well in regular driving as well as traffic light-to-traffic light performance.

How you intend to use the engine directly determines the type of cylinder head you should select. Budget street engines benefit more from the smaller ports we see with stock heads. They don’t always need porting and polishing, either. Sometimes porting and polishing take street power away from where you need it most. Stock intake ports that are rough cast keep fuel droplets in suspension on carburetor equipped engines. This improves low-end torque. Ground and polished intake ports can actually hurt low-end torque on carbureted engines because fuel atomization and suspension are affected.


One of the biggest myths you will face in your Ford engine build is that the 289 High Performance head is the best head to use. This is not necessarily so. The only difference between the 289 High Performance head and the 2V/4V head is valve spring pockets and screw-in rocker-arm studs. Otherwise, port size is virtually the same. So save your money and spruce up a set of 2V/4V heads or opt for 351W types. How? By doing some port work, opting for screw-in rocker-arm studs, and installing hardened valve seats and larger valves.
If you’re building a 289 High Performance engine, opt for larger 1.94/1.60" Chevrolet valves (no one’s going to know they’re there but you) and a port/bowl job to achieve the most from those factory Hi-Po heads. Externally, they will look stock. Internally, they will help your 289 High Performance engine breathe like it never has before. You can also opt for 351W heads here too without anyone knowing the difference externally.

Vintage small-block Ford head choices aren’t as simple as they may appear. There has been significant change in the 221/260/289/302 head over the past four decades. Some of these heads are best avoided. Others are diamonds in the rough.

The best small-block head to use is the 1969-73 351W, thanks to its larger valves and ports. It’s a bolt-on swap. When a 351W head cannot be sourced, the 1965-73 289/302 head is your best bet, due to its smaller wedge chambers. We stress head use prior to 1974 because combustion chamber size remains smaller in those years, keeping compression healthy.

When you are building a set of heads, good machining technique is important. First, castings should be checked for cracks and serious warpage. Then head deck surfaces should be checked and milled as necessary. Valves and guides should be reworked or replaced. Hardened exhaust valve seats should be installed. Pushrod guide plates and screw-in rocker-arm studs should be fitted. When budget is limited, you should opt for 1965 through early 1966 heads with pushrod guides already cast. If you are running a hot camshaft, screw-in rocker-arm studs become mandatory. When screw-in studs are beyond your budget, pinning the press-in studs becomes an inexpensive alternative.

Bush Performance in Fort Smith, Arkansas offers a low-cost way to get into hot street performance with the Street Boss system (nicknamed the “Clevor”, for Cleveland and Windsor). The Street Boss system puts the 351C head atop the 289/302/351W block. The way you intend to use your engine determines which 351C head you will use. For the weekend racer, the 351C-4V head with its large ports and closed-wedge chambers makes a good high-rev head. The 351C-4V head breathes very well at high RPM like we see in drag and road-course racing. The 351C-2V head is a better street head due to its smaller ports and open-chamber design. Smaller ports give you better low-end torque. Open chambers reduce the risk of detonation with low-octane fuels.

The 1969-73 351W head is a budget performance bolt-on for 289/302ci engines due to its larger valves and ports. The only important difference to watch for is the dog-leg coolant passage between the intake manifold and cylinder head on early 351W heads. This can pose leak problems if you use the wrong intake gasket. Use the 351W intake manifold gasket.

New aftermarket heads aren’t within the realm of a budget build. However, as they age and see use, they often wind up at the swap meets for considerably less than they were new. Glass beading and valve work makes them as good as new for less money. Good street heads include the Ford Motorsport SVO GT-40 iron and aluminum heads, World Products Windsor Jr. heads, and Edelbrock Performers. These are the most common, most reliable heads out there for the builder on a budget.

For those of you building late-model 5.0L and 5.8L engines, cylinder head choices tend to be different, especially if you’re interested in meeting emission standards. From 1982-84, Ford used a D9AE-6049-AA cylinder head casting atop the 5.0L High Output V-8. This is not a high-performance cylinder head although it was used on the 1982-84 5.0L High Output engines. It is, however, a workable cylinder head that will come alive with port work and larger 1.94/1.60" Chevrolet valves.

Small-block Ford heads lost yardage in the performance arena after 1978 with Ford’s increasing attention to emissions and driveability. Ports became smaller for improved low-end torque and cleaner emissions. Although this works well in traffic, it doesn’t do much for our engine in higher RPM ranges. Despite the D9AE casting shortcomings, you can still port these heads and make power. However, this is not maximizing what you can do with a stock cylinder head.
The biggest shortcoming with the D9AE casting is the exhaust port with Ford’s infamous Thermactor injection “hump” in the port. It becomes very restrictive. However, this hump can be ground out and all restriction taken away with some Saturday afternoon labor on a work bench. For 1985 only, Ford went to the E5AE head, which was little more than a modified D9AE casting designed for easy roller tappet removal with the head installed. It is identifiable by the reliefs notched in the head at the lifter valley. Otherwise, it is virtually identical to the D9AE casting.
Ford began making improvements to the 5.0L/5.8L head in 1986 with the “high-swirl/fast burn” E6AE and E6TE castings. This head saw widespread use from 1986-88 depending on vehicle application. A shrouded intake valve was trademark to the “high-swirl/fast burn” concept. Thing is, the E6AE/E6TE head didn’t do much for power.

The E5TE and E7TE heads introduced for 1987 are undoubtedly the best late-model castings because the “high-swirl/fast burn” chamber is eliminated. This is more a return to the 1985 High Output/Truck head with improved water jacket passages. For you the engine builder, this head is good for an easy bonus 25-30 horsepower.

The 1993-95 Cobra GT-40 head is little more than a marine head with larger valves and ports. This fact all by itself makes the GT-40 a good, economical head for 5.0L/5.8L performance. Economical because it is a common head. Just look for 1.84/1.54" valves, “GT” markings, and F3ZE/F4ZE casting numbers. Ford part numbers are F3ZZ-A and F4ZZ-A. These heads are also available from Ford Racing as M-6049-L302. Properly outfitted, these heads use the F3ZZ-6564-A roller rocker arm with a 1.7:1 ratio.

Camshaft and Valvetrain

The camshaft and valvetrain directly determine not only an engine’s personality, but how reliably it will perform throughout its service life. Unfortunately, a lot of folks have more misconceptions about camshafts than they have facts. Hopefully, in the following pages we can set you straight on the myths and get you headed in the right direction.

To understand how to pick a camshaft and valvetrain, you must first understand how it all works. Choosing a camshaft profile must be based on how you want an engine to perform. Are you building a streetable engine where low- and mid-range torque are important? Or are you building a high-performance racing engine that makes peak torque in the high revs? Whatever the application, it is vital for you to choose the right combination of components.

A camshaft manufacturer’s catalog lists dozens of camshaft types for the same type of engine. This is where it gets mighty confusing for the novice. We see words like lift, duration, lobe separation, base circle, lobe centerline angle, and valve overlap. What does all of this information mean and how will it affect your engine’s performance?


What makes one camshaft different from another? Call it profile. Profile refers to the lobe’s design, dimension, and positioning, as well as its functionality. Functionality refers to when the lobe opens the valve, when it closes the valve, how long it keeps the valve open, and how much it opens the valve. All of these factors influence an engine’s performance.

Following are a few terms that you will hear in the shop when talk turns to camshafts. Lift is the maximum amount a lobe will open a valve. Duration refers to how long the lobe will keep the valve open. Lobe Separation or center line is the time or duration between intake and exhaust valve action. Overlap plays into lobe separation because it is the period when the exhaust valve is closing and the intake valve is opening. The Ramp is the ascending or descending side of the cam lobe coming off the base circle when lift begins to occur. The Flank is the ascending or descending portion of the lobe past the base circle nearest maximum lift. The camshaft’s Base Circle is the portion of the lobe that doesn’t generate lift. The bottom-most portion of the lobe is called the Heel.

Flat-tappet camshafts work differently than roller-tappet camshafts, which means you have to think differently with each type. Flat-tappet camshafts limit what you can do with lobe profile
if you want street-ability. If you want an aggressive profile with flat tappets, you can only go so far with a street engine or suffer with poor drive-ability (rough idle, low manifold vacuum). If
you want an aggressive profile in a street engine, we suggest stepping up to a roller camshaft, which can handle the aggressive profile better using roller tappets.


Based on everything we have seen in nearly 30 years of experience, the best street performance cams are ground with a lobe separation between 108 to 114 degrees. When you keep lobe separation around 112 degrees, you improve drive-ability because the engine idles smoother and makes better low-end torque. This is what you want from a street engine. Any time lobe separation is below 108 degrees, idle quality and streetability suffer. However, there is more to it than just lobe separation.

Compression and cam timing must be considered together because one always affects the other. Valve timing events directly affect cylinder pressure. Long intake valve duration reduces cylinder pressure. Shorter duration increases cylinder pressure. Too much cylinder pressure can cause detonation (pinging). Too little and you lose torque. You can count on cam manufacturers to figure stock compression ratios into their camshaft selection tables, which makes choosing a camshaft easier than it has ever been. Plug your application into the equation and you will be pleased with the results most of the time.

The greatest advice we can offer the layman is to be conservative with your cam specs if you want reliability and an engine that will live a long time. Stay with a conservative lift profile (under .500-in. lift). A high-lift camshaft will beat the daylights out of a valvetrain, and will put valve-to-piston clearances at risk. Watch duration and lobe separation closely, which will help you be more effective in camshaft selection. Instead of opening the valve more (lift), we want to open it longer (duration) and in better efficiency with piston timing (overlap or lobe separation).
Always bear in mind what you are going to have for induction, heads, and exhaust. The savvy engine builder understands that in order to work effectively, an engine must have matched components. Cam, valvetrain, heads, intake manifold, and exhaust system must all work as a team. If you are opting for stock heads, your cam profile doesn’t need to be aggressive. Select a cam profile that will give you good low- and mid-range torque. Torque doesn’t do you any good on the street when it happens at 6500 rpm. Choose a cam profile that will make good torque between 2500 and 4500 rpm. Otherwise, you are just wasting engine.

The thing to remember with camshaft selection is how the cam will work with your engine’s cylinder heads. We need to take a close look at valve lift with a particular head and determine effect. Some camshafts will actually lose power with a given head because there’s too much lift or duration. This is why it is important to understand a given cylinder head before choosing a camshaft. You want to seek optimum with any cylinder head/camshaft combination. This means having to really do your homework before making a decision. Part of building a successful budget engine is doing a lot of the homework yourself because you cannot afford a wasteful experience.

What type of fuel do you intend to run in your engine? This also affects camshaft selection. We can actually raise compression if we’re running a mild camshaft profile or using a higher octane fuel. It all has to work together. Camshaft timing events must be directly tied to actually raise compression if we’re running a mild camshaft profile or using a higher octane fuel. It all has to work together. Camshaft timing events must be directly tied to compression ratio. The longer our duration, the lower the cylinder pressure and resulting compression. The shorter the duration, the less air we’re going to bring into the cylinder, which also affects compression. Our objective needs to be the highest compression without detonation, which will harm the engine. With this in mind, we want the most duration possible without compression extremes. Duration is what gives us torque as long as compression is sufficient.

Valve overlap, as we have stated earlier, is the period between exhaust stroke and intake stroke when both valves are slightly open. This occurs to improve exhaust scavenging by allowing the incoming intake charge to push remaining exhaust gasses out via the closing exhaust valve. Were the exhaust valve completely closed, we wouldn’t get scavenging. The greater the overlap in a street engine, the less torque the engine will make down low where we need it most. This is why we want less valve overlap in a street engine and more in a racing engine, which will make its torque at high RPM. Increased valve overlap works best at high RPM.

Street engines need 10 to 55 degrees of valve overlap to be effective torque powerhouses. When valve overlap starts wandering above 55 degrees, torque on the low end begins to go away. A really hot street engine will need greater than 55 degrees of valve overlap, but not much greater. To give you an idea of what we’re talking about, racing engines need 70 to 115 degrees of valve overlap.

Camshaft design can be confusing. Think of the cam lobe in geographical regions as it travels against the lifter: opening ramp, opening flank, nose, closing flank, closing ramp, then the heel. The base circle is the part of the lobe that doesn’t generate lift.

For a street engine, we want valve overlap to maximize torque, which means a conservative approach in the first place. Push overlap as far as you can without compromising torque. We also have to figure in lift and duration with valve overlap to see the complete power picture.
Lobe separation angle is another area of consideration in street cam selection. This camshaft dynamic is chosen based on displacement and how the engine will be used. Rule of thumb is this. Consider lobe separation based on how much displacement and valving you’re going to be using. The smaller the valves, the tighter (fewer degrees) lobe separation should be. However, tighter lobe separation does adversely affect idle quality. This is why most camshaft manufacturers spec their cams with wider lobe separations than the custom grinders.
Duration in a street engine is likely the most important dynamic to consider in the selection process. We increase duration whenever less lift is desired. Why? Because we get air flow into the cylinder bore two ways: lift and duration. We can open the valve more and for less time to get air flow. Or, we can open the valve less and keep it open longer via duration to get air flow. Each way will have a different effect on performance. Duration is determined by how much cylinder head and displacement you have, and how the engine will be used. Excessive duration hurts low-end torque, which is what we need on the street. So we have to achieve a balance by maximizing duration without a loss in low-end torque. We do this by using the right heads with proper valve sizing. Large valves and ports don’t work well at all for street use. Mix in too much duration and you have a real slug at the traffic light.

This is a flat-tappet camshaft. Notice the cam lobe profile (shape). It is more aggressive by nature even with a stock grind. Streetability suffers when lift and duration are increased, making the idle rough and eroding manifold vacuum.

So what does this tell us about duration? Plenty. We want greater duration whenever displacement and valve sizing go up. Increasing duration falls directly in line with torque peak and RPM range. This does not mean we necessarily gain any torque as RPM increases. It means our peak torque simply comes in at a higher RPM range. An example of this is if our engine is making 350 ft./lbs. of torque at 4500 rpm and we increase duration. We may well be making that same amount of torque at 5200 rpm. In short, increased duration does not always mean increased torque.

Compression has a direct effect on what our duration should be. When we’re running greater compression, we have to watch duration closely because it can drive cylinder pressures too high. Sometimes we curb compression and run greater duration depending on how we want to make power. When we have greater duration, our engine is going to make more power on the high end and less on the low end. This is why you must carefully consider duration when ordering a camshaft. Higher compression with a shorter duration helps the engine make torque down low where we need it most in a street engine. The thing to watch for with compression is detonation and overheating. Maximum street compression should be around 10.0:1.

Valve lift is an issue we must think about as it pertains to an engine’s needs. Small blocks generally need more valve lift than big blocks. As we increase lift, generally we increase torque. This is especially important at low- and mid-RPM ranges where it counts on the street. Low-end torque is harder to achieve with a small block because these engines generally sport short strokes and large bores. Your objective needs to be more torque with less RPM if you want your engine to live longer. Revs are what drain the life out of an engine more quickly.
To make good low-end torque with a small block, we need a camshaft that will offer a combination of effective lift and duration. As a rule, we want to run a longer intake duration to make the most of valve lift. We get valve lift via the camshaft to be sure. However, rocker arm ratio is the other half of the equation. The most common rocker arm ratio is 1.6:1, which means the rocker arm will give the valve 1.6 times the lift we have at the camlobe. When we step up to a 1.7:1 ratio rocker arm, valve lift becomes 1.7 times that which we find at the lobe.

When we’re spec’ing a valvetrain, it is best to achieve balance all around. If you run a high-lift camshaft with a 1.7:1 rocker arm ratio, you may be getting too much lift, which means excessive wear and tear. It is best to spec on the side of conservatism especially if you’re building an engine for daily use. Whenever you opt for an aggressive camshaft with a lot of lift, you’re putting more stress on the valve stem, guide, and spring. The constant hammering of daily use with excessive lift is what kills engines without warning.

We will take this excessive wear logic a step further. It is vital that you ascertain proper centering of the rocker arm tip on the valve stem tip when you’re setting up the valve train. We do this by using the correct length pushrod for the application. Buy a pushrod checker at your favorite speed shop if ever you’re in doubt. A pushrod checker is little more than an adjustable pushrod that you can use to determine rocker arm geometry. If the pushrod is too long, the tip will be under-centered on the valve stem, causing excessive side loads toward the outside of the cylinder head. If the pushrod is too short, the rocker arm tip will be over-centered, causing excessive side loading toward the inside of the head. In either case, side loads on the valve stem and guide cause excessive wear and early failure. This is why we want the rocker arm tip to be properly centered on the valve stem for smooth operation.

One accessory that will reduce valve stem tip wear and side loading is the roller-tip rocker arm. Roller-tip rocker arms roll smoothly across the valve stem tip virtually eliminating wear. Stamped-steel, roller-tip rocker arms are available at budget prices without the high cost of extruded or forged pieces.

Induction Systems

One true measure of an engine’s potential sits on top when it’s time to button up the mill. The induction system — also called the intake manifold, carburetor, or fuel injection — influences an engine’s performance as much as the camshaft and cylinder heads. Under ideal circumstances, you will have a perfect marriage between heads, camshaft, induction, and exhaust system. In the power picture, it is all about the proper packaging of parts that work well together. Not enough of us are getting that right.


Carbureted street engines need long intake runners in order to produce good low- and mid-range torque. Longer intake runners are found in dual-plane intake manifolds like the Edelbrock Performer and Weiand Stealth. Installing an aftermarket manifold like the Performer or Stealth improves performance because it improves airflow velocity into the combustion chambers. This is likely one of the best modifications you can make to a street engine without selling off the farm.

Dual-plane/high-rise manifolds don’t always have to be new ones, either. Vintage Cobra and Edelbrock dual-plane/high-rise manifolds yield the benefits of low-end torque and high-RPM breathability, and they can be readily found at swap meets. They do well on the street in stop-and-go driving, and they yield plenty of power when it’s time to rock. Single-plane intake manifolds like the Edelbrock Torker, Torker II, Tarantula, and even the Streetmaster are not the best street manifolds because they are designed to make torque at 3000 to 7000 rpm, yet we see them on a wide variety of street engines where a good dual-plane manifold would work much better.

Long intake runners and a dual-plane design are but two reasons why we can achieve good low- and mid-range torque from a carbureted engine. We also want cool air both ahead of the carburetor and beneath it. To get cool air before the carburetor, we need to source cool air from outside. Underhood air is much hotter than the ambient air outside. If we can drop the intake air temperature by 50 to 80 degrees F, this will make a considerable difference in thermal expansion inside the combustion chamber. We can net nearly 10 percent more power this way.
We get cooler air with a hood scoop or a ram-air scoop at the leading edge of the vehicle. Ram air can be sourced through the radiator support or beneath the front bumper. Ram-air kits can be purchased from Summit Racing Equipment, Performance Automotive Warehouse (PAW), or your favorite speed shop. The choice is yours.

Getting cool induction air after the carburetor takes closing off the manifold heat passages from the exhaust side of the cylinder head. We do this during intake manifold installation by installing the manifold heat block-off plates included in most intake manifold gasket kits. Manifold heat is needed only when the outside air is really cold. A cold intake manifold allows the fuel to atomize as well as it does in a hot manifold which causes hesitation and stumbling. We curb this problem by adjusting the choke to remain on for a longer period of time. Then, when the engine is warm, we still have a cooler manifold that offers us better performance.

A popular myth is that we make more power by removing the air cleaner. The truth is, removing the air cleaner allows dirt and grit inside your engine which shortens engine life. We want a low restriction air cleaner that will effectively filter out dirt while allowing healthy breathing at the same time. K&N air filters meet the mission effectively, but they don’t come cheap. Filters for
carbureted applications cost around $45 each retail. They can be washed and reused, which actually saves you money long term because K&N claims these filters will last a million miles. What’s more, they outperform the nearest competitor by a wide margin. A K&N air filter is money well spent in terms of performance and longevity. The new K&N filter with a separate filter in the lid improves breathing even more.

One of the biggest mistakes enthusiasts make is overcarburetion. Engines don’t need as much carburetion as you might think. The formula is simple, and without a lot of complex engine math. Small blocks ranging from 221 to 302 cubic inches need no more than 500 cfm. The 351W and 351C need 500 to 600 cfm. Big blocks displacing 352 to 390 cubic inches need 600 to 650 cfm. Larger big blocks of 406 to 428 inches need 650 to 750 cfm. These numbers may sound modest, but they are all a healthy street engine needs. We have to laugh whenever we see a mildly modified street small block with a 750 cfm Holley double-pumper. That’s way too much carburetor.

The exception to our carburetion formula is racing applications. When we’re going racing, our engine needs more carburetor if it’s going to make torque. Small blocks can tolerate 600 - 650cfm in racing applications. Middle- and big-block applications up to 390ci need 700 - 850 cfm. Beyond 390ci, we need 850 - 1050 cfm. Performance tuning is where we learn how much carburetor we’re going to need.

Overcarburetion wastes fuel and pollutes the air. Too much fuel is also hard on an engine. It washes precious lubricating oil off the cylinder walls and fouls spark plugs. Your performance objective should include being environmentally responsible. Plan and tune for cleaner air, not just power. There are three objectives in engine performance: efficiency, cleaner emissions, and power.

Through the years, we have seen and used a wide variety of carburetors on Ford V-8s. Although the Holley 1850, 4150, and 4160 are legendary performance carburetors, they don’t enjoy the reliability of an Autolite 4100 — that plain-Jane four-throat carburetor Ford installed on a wide variety of V-8s from 1957-66. The 4100 is fiercely reliable and it offers the same level of performance we’re used to with the Holley. Holley carburetors struggle with bowl leakage and metering block difficulties. Metering block passages tend to clog easily, causing idle and driveability problems. We don’t see these problems on the Autolite 4100. Some Holley carbs perform well for years, while others tend to be high maintenance. The 1850, 4150, and 4160 can be challenging due to their small metering block passages that tend to become clogged. The 600cfm 1850 series Holley is the biggest culprit for driveability problems shortly after it comes out of the box or through a rebuild. When this carburetor won’t idle right and won’t adjust, remove the metering block and its plugs. You will find the idle/air bleeds plugged with dirt. Deal with this size issue with either periodic metering block cleanings or a different metering block with larger passages. This is a problematic issue common to most Holley carburetors.
Anyway you look at Holley carburetors, they are high maintenance despite what all of the Holley die-hards will tell you. Because racing and performance driving tends to be high-maintenance by nature, Holley’s engineering woes tend to be lost in the shuffle. Despite these observations about the Holley, it remains the most widely used performance carburetor in the world because it is easy to service and understand. Jet, power valve, and metering block swaps are simple with the Holley, which makes it popular with racers.

For street engines, we suggest a Holley with vacuum secondaries for a smooth transition into high power. Vacuum secondaries work better in street use because they function only when we need them at wide-open throttle. Mechanical secondaries make more sense in racing use because they come into play more quickly in a linear fashion.
Our message here for the street buff is simple: Be realistic about how you will use your engine. Most of your driving will be normal stop and go with open highway tossed in for good mix. Weekend drag racing will be the exception, not the rule. Build an engine you can live with on a daily basis, then make tuning changes for weekend fun. You need an intake manifold and carburetor that will give you good acceleration and driveability coupled with clean emissions. Companies like Edelbrock and Weiand have done extensive research to improve the performance of their products, including improved emissions. Good dual-plane street manifolds like the Performer and Stealth get the job done nicely.

Street engines need long intake runners such as those found in the Weiand Stealth dual-plane intake manifold. This manifold fits comfortably underneath any hood using a stock or aftermarket air cleaner. A Holley 1850, Carter AFB, or Autolite 4100 carburetor will work fine with this manifold.

The Autolite 4100 mentioned earlier is a better street performance carburetor than the Holley from a reliability standpoint. It delivers plenty of power on demand and will go for years without much in the way of service. The only exception to this rule is California with its destructive oxygenated fuels that harm older fuel systems. You can expect failing gaskets, seals, and rubber hoses with the California fuel additive MTBE. For California vehicles, we suggest hard lining your fuel system between the fuel pump and carburetor and the use of steel-reinforced hoses where necessary to prevent fuel leakage and fires.

When your performance requirements mandate something more aggressive than the Autolite 4100, opt for that weekend Holley racing experience with a simple carb swap when you want to go racing. Holley and Autolite carburetorsare easily interchanged in an afternoon, which enables you to live peacefully with both.

Where carbureted induction systems become tricky is late-model 5.0L High Output V-8 engines because we must build an engine that will pass both a visual and tailpipe emissions smog check. Although you might be tempted to dig your heels in on this one, your goal should always be cleaner emissions for the daily driver.

Ford first began using cast-aluminum intake manifolds in 1979 atop the 302-2V V-8. In 1979, it was a dual-plane, two-barrel manifold. In 1980-81, it was a 255ci small block with different cylinder heads and a 255-specific intake manifold. The 255ci small block had different intake ports than we find on the 302 (smaller for improved torque from less displacement). For 1982, the 5.0L High Output V-8 had a cast-aluminum, two-barrel, dual-plane intake manifold not much different than what we had in 1979.

Ford used two basic types of carburetors in 1977-81 atop small-block V-8s. The Motorcraft Variable Venturi (VV) two-barrel carburetor is an interesting chapter in Ford V-8 history. Known as the Motorcraft 2700VV, this carburetor family is nothing like a conventional carburetor because, as its name implies, the venturis vary in size depending on load and the demand for power. Venturi size depends on throttle position. Metering rods tied to the venturis determine fuel delivery. The VV carburetor is not a popular fuel metering device, so we won’t go into much detail here. Suffice it to say this carburetor was conceived for cleaner emissions, not performance. Because VV cores are outrageously priced at $500+, they don’t fall inside the guidelines for a budget V-8. If you can get by without using a 2700VV carburetor, do it.
At the same time, Ford also used the Motorcraft 2150 two-barrel carburetor (depending on where the vehicle was delivered new). Like the earlier Autolite and Motorcraft 2100 carburetor, the late-model 2150 is a fiercely reliable carburetor due to its simple design. We’re convinced you probably won’t be using this carburetor on your high-performance budget small-block. However, emission laws being what they are in different parts of the country, you could be forced to use original equipment to pass a smog check.

For 1983-85, Ford used a dual-plane, cast-aluminum manifold that incorporated four-barrel Holley carburetion. The most important thing to remember about the Holley 4180 carburetor is this: Although it looked similar to the time-proven Holley atomizers we’ve been playing with for more than 40 years, it is not a compatible carburetor with other Holley four-throaters. In fact, it is a Ford-designed carburetor produced by Holley for Ford exclusively. Holley produced a similar emissions/performance carburetor for Chevrolet’s 305ci small blocks of the period as well, much like Ford’s 4180C. The 600cfm Holley 4180C was not a feedback carburetor like a lot of carburetors of the period. This means there was no computer control aboard the 1983-85 Mustang GT, Capri RS, and LTD models fitted with the 5.0L-4V engine.

The 1983 5.0L-4V Holley 4180C is easily identified by the “LIST 50223” number stamped in the front of the air horn like other Holley carburetors. From 1984-85, the number changes to “LIST 50265”. The Holley 4180C was fitted on 5.0L High Output V-8s with five-speed transmissions. Those fitted with AOD automatic transmissions received Central Fuel Injection instead of Holley carburetion.

The Holley 4180C is not a performance carburetor despite its Holley name. It is configured for lean, clean emissions operation hence its reputation for flat spots and poor off-idle performance. You can make improvements to the metering block, power valve, and accelerator pump to net some improvement. In states with tough emission laws and regular smog checks, there is only so much you can do. Because the Ford/Holley 4180C has a Ford-specific metering block, it is not interchangeable with other Holley metering blocks.

On the secondary side of the 4180C, there is some interchangeability with other Holley carbs. The Holley 34-6 improvement kit enables you to improve the secondary metering side. However, because the fuel transfer tube is a tad short, you will have to use two “O” rings at the secondary side. The bottom line with the 4180C is that it is not a good performance carburetor. It is a Ford/Holley venture designed with clean emissions in mind. Holley does have some
performance improvement parts for this carburetor, but it remains a very limited carburetor. See Holley for more details.

Exhaust Systems

Exhaust systems have been the subject of hot debate for as long as there have been automobiles. Headers or stock manifolds? Long- or short-tube headers? What size exhaust pipes? Single or dual exhausts? What kind of muffler should I use? Must I use catalytic converters? Is louder better? Will my engine make more power with the headers uncapped?
In recent times we have been learning more about exhaust systems and their effect on power output. Contrary to what we believed for years, an engine can actually make more torque through mufflers than through open headers. In some cases, stock manifolds can even help an engine achieve better torque. Because exhaust system technology has changed considerably over the years, it’s time for a refresher course in what works well today.

An exhaust system actually begins at the exhaust valve and port. Good cylinder head porting should be the beginning of a well-thought-out exhaust system. We want smooth flow from the valve face through the port into the header tubes. Although we have covered cylinder head porting elsewhere in this book, we remind you to think about port work as it pertains to your exhaust system. You would be surprised how much power you can pick up with good exhaust system scavenging. Good scavenging is what makes a power pump out of a budget engine.
Think about exhaust tuning this way. During valve overlap, we’re moving unspent fuel and air into the chamber which pushes spent exhaust gasses out. If we’re doing this thing the right way, we tune our valve overlap (via the right camshaft selection) to move the fuel and air in just as smoothly as we move spent exhaust gasses out. This is where our exhaust system begins. With the right valve overlap, we create a smooth flow of energy and spent gasses through the engine.


There are four basic types of exhaust headers for V-8 Fords: tri-Y, equal length, four-tube, and shorty. Tri-Y headers were most popular during the 1960s when it was perceived they were the best idea. As engine power and speed have become more aggressive in the years since, it has been found that tri-Ys don’t perform as well in racing applications. Tri-Y headers work quite well on the street where good low- to mid-range torque is needed. Their smaller tubes and tri-Y design help maintain back pressure and separate the exhaust pulses for improved performance. Carroll Shelby’s GT350 Mustangs used the tri-Y header with great success during the 1960s. These retro-headers can work very well in your street small-block application.

Four-tube headers are the system used most often today. The tubes are as close to equal length as possible, although there are some exceptions. Ideally, a manufacturer will get tube length within one to two inches, depending upon the installation. Late-model Ford small-block, equal-length headers are typically shorties to where they can be tied into a Mustang’s dual-catalyst exhaust system. (You do want to be smog-legal, don’t you?) Equal-length, long-tube headers also exist for early- and late-model Fords alike. If what manufacturers offer isn’t sufficient to meet your specialized needs, you can fabricate your own headers via kits or simply raw materials from an exhaust shop.

Late-model 5.0L high-output exhaust headers offer a clean design — but breathing suffers. They are just too small and restrictive.

Header tube size is one of the most important issues facing the engine builder who is seeking power — and a larger tube isn’t always what your engine needs to make power. Smaller header tubes help an engine make better low- to mid-range torque, which is important on the street. Engine displacement and mission directly determine what tube size you are going to need. Header manufacturers have done most of the homework here already, making your job easier. Simply specify your application and intended use, and the rest is easy.

Header tubes that are too large take away the exhaust system’s ability to scavenge spent gasses. When you keep header tube size smaller, you are increasing exhaust velocity (speed), which helps draw gasses out more quickly. Smaller tubes help increase back pressure, which, thanks to valve overlap, helps you get the most out of a combustion charge. When header tube size becomes too large, velocity decreases and we lose exhaust scavenging.

Aftermarket shorty headers are the most logical first step to performance. They offer unobstructed breathing. Check your local emission laws before installing these. Legal or illegal, they look stock and don’t throw up the red flag like long-tube headers.

Tube thickness is also an important issue. Typically, header tube wall thickness ranges from 18 to 14 gauge, with the higher number being the thinner stock. For durability, you will want to opt for 16 or 14 gauge. Longevity comes from a thicker wall and durable coating. For street use, we recommend the thickest gauge, which is less likely to crack or split. Coatings range from spray-on paint that burns off to a Jet Hot coating that lasts the life of the header.

If you are building an engine for the long haul, we suggest Jet Hot Header Coatings (phone 800-432-3379). This process may cost more going in, but it means having headers that will never rust or rot through. It is the best ceramic header coating there is. Due to its very nature, it contains heat too, which keeps heat where it belongs -- inside the header for greatest efficiency. If you cannot afford Jet Hot, we suggest a super heat-resistant header paint. For the paint to set properly, you must begin with a clean surface. Clean the headers with brake cleaner, which has a high evaporation rate. Let them dry out in the sun, then apply high-temp paint in thin coats, allowing each coat to dry thoroughly before applying the next.


A terrific alternative to the shorty header is the 289 High Performance. The 289 High Performance exhaust manifold (A and C) is a factory cast-iron header. It offers improved breathing without clearance and heat issues. Manifolds B and D are standard 289/302 manifolds. See the differences?

Another important consideration when selecting headers is smog laws in your area. Some areas do not permit the use of headers on street-legal vehicles. Some areas permit only the use of EPA or CARB-certified (California Air Resources Board) headers. Check your local motor vehicle code before spending the money. Don’t kid yourself; smog checks nearly always spot the illegal beagles. If your state is big on visual inspections, running any kind of illegal header will be difficult, if not impossible. However, if you are dealing with a tail-pipe sniffer only, then opt for the best header for your application. Shorty headers are the best choice for an application where a stock appearance is important. Long-tube headers send up red flags immediately in a smog check. If you have eliminated the catalytic converter, it can get expensive in terms of fines and the installation of new converters.

Whenever you are shopping headers, always keep fitment in mind. Despite what manufacturers will tell you, not all headers fit. A good many will require some adjustment on your part. Always use high-temperature ignition wires that can withstand header heat, or install thermal boots and shields for protection. Some ignition wire manufacturers offer ceramic spark plug wire boots. If headers run close to the starter motor, heat issues apply here, too. Excessive header heat will shorten starter life. Sometimes heat disables the starter entirely. Thermal-wrapping the headers reduces underhood heat considerably. See your local speed shop for details.

Another thing to consider when you’re shopping for headers is quality. Look at the flange at the head and at the collector. Examine the welding. High-quality headers have welded flanges with a solid bead for 100 percent of the seam. Those with tack welds won’t last; they will leak.
Ford produced some respectable exhaust manifolds for its V-8 engines. For example, you can still buy reproduction 289 High Performance exhaust manifolds for your small-block Ford. These manifolds look like cast-iron exhaust headers and they tie nicely into virtually any exhaust system. A similar manifold to the 289 Hi-Po piece is the 1969-up 351W exhaust manifold. Like the Hi-Po manifold, these look like cast-iron headers. With some grinding and clean-up work, they look sharp and function well. These manifolds give a small-block Ford that deep, throaty sound 289 High Performance manifolds are famous for. Whenever you’re shopping stock cast-iron manifolds, you want to avoid the long, straight log types which are very restrictive.
Manifold selection for 335-series engines is poor. We can’t honestly recommend one. Ditto for 385-series big blocks. Manifolds in both instances are too restrictive. FE-series big blocks have wide selection. When it comes to FE-series big blocks, ideally you’re building a full-sized Ford or Merc that will accommodate 390/406/427 High Performance factory exhaust headers. These awesome cast-iron bananas look terrific and sound incredible. Unfortunately, they will not fit the more compact Fairlane and Mustang. There’s simply no room for them.

When it comes to late-model exhaust manifolds and headers, stock 5.0L shorty headers don’t impress. They’re too restrictive and the quality is poor. Opt for a nice set of quality aftermarket shorty headers, which will breathe better, last longer, and fit nicely. Among the best are JBA and Hedman headers. Late-model cast-iron exhaust manifolds are awful. Opt for aftermarket shorties or long tube headers that will go directly into the cats.

Ignition and Charging Systems

Few things about an engine build seem more mysterious and magical than the ignition system. There have been a lot of advances in ignition technology through the years. Not even 30 yeaars ago we were driving vehicles with crude point-triggered ignitions and conventional distributors. Keeping spark timing in sync with engine RPM has been a great challenge with conventional ignitions. With high-performance engines, keeping the spark alive at high revs under great combustion pressures has been asking a lot of those dated point-triggered ignitions.

Time and technology have brought us better ignition systems — even distributorless ignition, which is as precise as it gets. Because you’re building a budget V-8, distributorless ignition probably isn’t in the cards. So we have to concentrate on how to achieve precision ignition via the distributor. First, let’s look at the basics.


Conventional ignition systems consist of a primary and secondary circuit. The primary circuit consists of the battery, ignition switch, and the primary side of the ignition coil (positive terminal). The secondary circuit consists of the secondary side of the ignition coil (negative terminal), ignition harness, and spark plugs. Think of it this way: The primary circuit gets power to the ignition coil and the secondary circuit gets processed power to the spark plugs. We call it processed power because we are changing it from 12 volts to 10,000 to 30,000 volts to feed the spark plugs. A high-voltage spark is needed to bridge the spark plug gap.

To process and distribute power, we need an ignition coil, distributor, points, and condenser. Think of ignition points as a switch that is open and closed in time with the distributor. When the points are closed (switch on), the primary circuit side of the ignition coil is energized. When this happens, current flows from the ignition switch (via a resistor wire or ballast resistor) through the coil to the ignition points to ground. The points are a switch to ground. When current passes through the primary windings of the coil, a magnetic field builds up around these windings. As the distributor cam turns, the points open (switch off) and current stops flowing through the primary side of the coil windings. When this happens, the magnetic field collapses in the primary windings inside the coil. It then finds a path through the secondary windings inside the coil to create a very high electrical current that is routed to the spark plugs via the distributor rotor, cap, and wires. The condenser’s job is to limit the amount of current passing through the points, which prevents pitting and burning.

This is a simple single-point Autolite distributor with dual advance. The dual advance, which first saw use in 1968, both advances and retards the spark for improved emissions. Earlier Autolite distributors only advance the spark. All vacuum advances are adjustable either through shims (Ford) or with an Allen wrench (aftermarket).

Think of the ignition system as a voltage management-and-distribution operation. It has a tough job, and that is to keep the release of current to the spark plugs in perfect time with engine speed, load, and throttle position. At idle, the ignition system has an easy job. Contrary to what you might have been taught, fuel does not explode in the combustion chamber. It ignites in a “quick fire” just like your gas or oil burning furnace lights on a cold night. Because the fuel/air mix ignites in a quick fire, not an explosion, the spark must occur a given number of degrees of crank rotation before the piston reaches top-dead-center. Why? Because time passes from the time the spark plug fires until there is a productive mixture light-off with working heat and pressure. If we ignite the mixture with the piston at top-dead-center (TDC), we waste most of the charge because actual light-off doesn’t occur in that scenario until after top-dead-center (ATDC). The engine doesn’t make power in this case; it just burns and wastes fuel.

Ford’s Autolite dual-point distributor was installed on most factory high-performance V-8s throughout the 1960s. The use of dual points spread the load over two sets of ignition points, providing a more precise spark at high revs. Most Ford dual-point distributors did not have a vacuum advance unit because these distributors did their best work at high RPM. Beginning in 1969, Ford fitted the dual-point with a dual-advance unit for improved emissions.

If our specifications call for static timing of six degrees before top-dead-center (BTDC), this means it is going to take six degrees of crank rotation and piston travel before the ignited mixture will work for us. When the spark plug fires at six degrees BTDC, mixture light-off happens before the piston gets to the top of the bore. By the time the piston reaches the top of the bore, light-off is well underway and we have a useful charge to drive the piston down the bore, which turns the crankshaft and makes power along with seven other cylinders on the same timed mission.
As engine RPM and power demands increase, the spark must occur earlier in the cycle. This is where two forms of spark advance come in — vacuum and mechanical. In vacuum-advance distributors, both vacuum and centrifugal advance units work together in seamless harmony for the solid application of engine torque. The vacuum advance advances the spark during engine acceleration. Leaning on the gas advances the spark via a vacuum advance diaphragm unit. This helps the engine produce torque under acceleration. The vacuum advance should smoothly give way to the centrifugal advance as RPMs increase — that is, if timing is where it should be.

Sometimes we have too much timing (too much spark advance), causing the spark to occur too early. When this happens, we have pre-ignition, or detonation, meaning the fuel ignites prematurely. The combustion shock against the piston dome creates a rapping or rattling we hear as “pinging” under acceleration. It is a popular misconception that this sound is caused by valves knocking or by rod bearing noise. It is neither. Rather, it is piston wrist pin and skirt noise caused by the abnormal combustion shock that goes with detonation/pre-ignition.
The centrifugal advance advances the spark at a slower rate and more at higher revs. Flyweights and springs tied to the distributor shaft work together and advance the rotor position according to RPM. The more RPM we have, the more the flyweights advance the spark. Spring tension retards the spark as RPM decreases.

For cohesive spark advance operation, you need to program both the vacuum and centrifugal advances to advance the spark smoothly as the need for power comes into play. If both forms of advance are in perfect tune, the vacuum advance will hand off its duties to the centrifugal advance as engine speed increases. Too much vacuum advance too early will cause the engine to ping or misfire. Too little and the engine will fail to produce sufficient torque under acceleration. It will fall on its face. The same goes for the centrifugal advance at higher RPM. Too much spring tension and it will not advance. Too little and it will advance too early.
A distributor’s advance process must be tuned in steps. First, you program the centrifugal advance to come in fully by the time an engine reaches a given RPM range. For street engines, full advance should come in around 3500 rpm. Full advance should be roughly 36-40 degrees BTDC. You dial in centrifugal advance with the right combination of flyweight weight and spring tension. As stated earlier, the greater the spring tension, the more slowly the distributor will advance. Remember, the spring’s job is to retard the spark. The flyweight’s job is to advance the spark. The object is to get these guys working together smoothly.

Programming the vacuum advance takes the right combination of vacuum and spring pressure inside the advance. The more spring pressure you have, the more slowly the vacuum advance will come into play. Spring pressure fights the vacuum. Vacuum fights the spring pressure. Vacuum advances the spark. Spring pressure retards the spark. You want a balance here where vacuum advances the spark smoothly while you are leaning on the throttle.

Older Autolite distributors have adjustable vacuum-advance units that use shims against spring pressure. The more shims you add, the greater the spring pressure and the slower the advance rate. When you remove shims, you decrease spring pressure and increase the rate of advance. If your Autolite distributor is vacuum-advancing too quickly (which will cause misfire and rough operation), you need to add shims one at a time. If it doesn’t advance quickly enough (resulting in sluggish performance), then you need to remove shims one at a time.

Replacement vacuum-advance units for Autolite and Motorcraft distributors are adjustable using an Allen wrench through the vacuum hose port. Turn the Allen wrench clockwise to increase spring pressure, or counterclockwise to decrease spring pressure.

This brings us to Autolite/Motorcraft dual-point performance distributors. A dual-point ignition allows for a more positive saturation of the ignition coil at high revs, which is why we have two sets of ignition points tied together in series. Prior to 1972, Ford used dual-point, mechanical-advance distributors in high-performance applications like the 390, 406, and 427 High Performance, the 289 High Performance, the Boss 302, 351, and 429 V-8s. In earlier applications like the 289, 390, 406, and 427 High Performance V-8s, the C5OZ-12127-E dual-point distributor was a mechanical-advance only for high-RPM use. Because these engines come on strong at 6000 rpm, this is where a mechanical (centrifugal) advance does its best work. Ignition timing at idle with this distributor is 12 degrees BTDC. Based on a lot of engine-tuning experience, you can push this distributor to 16 degrees BTDC at idle. The main thing to remember is not to allow total advance to go beyond 36 to 40 degrees BTDC at 3500 rpm.
The 1969-70 Boss 302 dual-point distributor had a dual-advance unit that both advanced and retarded the spark. Under acceleration, the spark was advanced. During deceleration, the spark was retarded to reduce exhaust emissions.

Like the conventional single-point Autolite/Motorcraft distributor, the dual-point’s centrifugal advance comes into play based on distributor speed, flyweight weight, and spring tension. The greater the spring tension, the later the centrifugal advance comes on-line. Likewise, the heavier the flyweights or weaker the springs, the earlier the spark advance comes into play. This is something you have to play with either in the engine with a road test or in a distributor test fixture. You know the advance is programmed right when there is a solid application of torque as RPMs increase. If there is pinging (detonation), the advance is coming on too soon. Then it’s a matter of calibration with the use of different springs primarily. To slow the rate of advance, use a stronger spring.

Beginning in 1969, Ford used a dual-point Autolite distributor with a vacuum dual-advance unit for improved emissions. The dual-point ignition allowed for better performance at high revs. The dual-advance unit was designed both to advance under acceleration and retard the spark during deceleration. Retarding the spark during deceleration reduces hydrocarbon emissions. Vacuum switching based on engine coolant temperature is what determines whether or not you get spark advance or retard. Suffice it to say that the dual-advance unit was one of Ford’s first steps toward more in-depth engine emissions management.


In 1974, Ford began using an electronic ignition system known as Duraspark. The Duraspark ignition system consists of a Motorcraft distributor with a magnetic pick-up and an ignition amplifier that mounts on the inner fender or firewall. The Duraspark ignition system is simple to install and use. Since the Duraspark system has been installed in millions of vehicles since 1974, cores are plentiful from salvage yards. What’s more, it is a proven ignition system with an excellent track record. You can even purchase a re-manufactured Duraspark distributor and a new aftermarket ignition amplifier from your local auto parts store. Duraspark ignitions are available for all Ford V-8s except the Y-Block and MEL-series V-8s. Both of these engines were discontinued for more than a decade prior to the availability of Duraspark.

The Duraspark ignition system can be installed with the amplifier visible or invisible. Invisible, you can hide it in the fender well (shielded properly from dirt and water) or inside the firewall under the dashboard. All the amplifier needs is adequate airflow for cooling purposes.
There are three types of Duraspark ignition systems. Duraspark I is the first generation, with a very simple distributor and amplifier package common during the 1970s. Duraspark II is an advanced form of Duraspark I, more tied to engine function. Duraspark III has a crankshaft sensor that makes it more an electronic engine control system. For your budget V-8, we suggest the original Duraspark I system.

Two types of distributors were used on early 5.0L high-output V-8s. Carbureted versions were fitted with a magnetic-trigger Motorcraft Duraspark distributor from 1979-85. Those fitted with CFI or SEFI (fuel injection) were fitted with a different type of Motorcraft distributor that works on the Hall Effect concept.

Magnetic trigger is a conventional electronic ignition (Duraspark) that uses a pick-up module and an eight-point reluctor attached to the distributor shaft. The armature whirls around with the shaft in time with the engine’s camshaft. The pick-up module senses a disruption in the magnetic field, which switches the ignition coil on and off, just like ignition points and condenser did in the old days. For the most part, the mag-trigger distributor is trouble-free. It works on conventional ignition principles with both a vacuum and centrifugal advance like an older Ford V-8 engine. The last year Ford used this distributor was 1985 on the 5.0L-4V HighOutput V-8.

Hall Effect distributors are computer controlled, part of a complete engine-control package called EEC-IV (Electronic Engine Control, Fourth Generation). EEC-IV first saw use on the Thunderbird Turbo Coupe, Cougar XR-7 Turbo, and the Mustang SVO. It was used with Duraspark III. The 2.3L Turbo OHC four that powered these cars needed a precision system that would allow smooth, safe operation. EEC-IV did a good job of controlling spark, fuel, and boost curves for smooth operation. Ford applied EEC-IV to CFI first in 1984, then SEFI in 1986 when port fuel injection came to the V-8 arena. EEC-IV is a programmable system, in which you can adjust fuel and spark curves with a laptop computer.

The Hall Effect Motorcraft distributor is a conventional distributor fitted with a TFI (thick film integrated) module, profile ignition pickup (PIP), trigger wheel, and a Hall Effect switch. The trigger wheel rotates on the distributor shaft, interrupting a stationary magnet and a current carrying Hall Effect semi-conductor. As the trigger rotates between these two elements, it provides a signal for the EEC-IV system. It also allows for coil saturation and the release of high-voltage electricity to the spark plugs. A crankshaft sensor takes care of the rest of the EEC-IV triggering system.

The TFI module does what a vacuum and centrifugal advance used to do. It also controls coil discharge and dwell timing. This means the TFI module does the same job that points, condenser, and advance units used to do. Doing all of this work makes the TFI module run hot. It has a reputation for failure due to heat issues. One solution is to use dielectric grease between the TFI module and the distributor during installation. One other solution is to retrofit your 5.0L HighOutput V-8 with a 1994-95 Motorcraft distributor where the TFI module has been moved out of the distributor to the inner fender for cooler operation.

We are sometimes asked which is the best aftermarket ignition system for a budget 5.0L/5.8L SEFI V-8. The truth is, the stock Motorcraft EEC-IV system provides all of the ignition power your budget V-8 will ever need. It packs a wallop at nearly 40,000 volts at the spark plugs. So save your money and invest it in what is really important inside the budget engine.


Stock Ford distributors have one major shortcoming: their shaft bushings don’t receive sufficient lubrication for long life. They wear out quickly. As a result, excessive shaft-side play causes irregularities in point dwell and gap. The aftermarket offers alternatives to the stock Ford ignition system.

If you are attached to your stock Ford distributor, Pertronix has fast answers with its Ignitor and Ignitor II retrofit ignition modules. The Ignitor module installs in 15 minutes and never requires service for the life of the module. Remove the ignition points and condenser. Then fasten the Ignitor to the breaker plate and connect the leads, just like you would a set of points. Then set the air gap and install the shutter wheel. Pop on the rotor and distributor cap, and the job is finished. The beauty of the Ignitor is its simplicity. No periodic maintenance required and no one knows it’s there but you. It’s perfect for the stock, original driver that you would like to keep stock in appearance. One more thing about the Ignitor. Should it fail, you can reinstall the points and condenser, which will get you back on the road in short order. The Ignitor has an excellent reputation for reliability, so failure is uncommon.

If when you install the Ignitor the engine will not start, or operation is erratic, check the ground first. There should be a ground strap between the breaker plate and the distributor housing, just like Ford did it from the factory. If the ground strip is missing, the engine likely will not start, or it will mysteriously shut down and not restart.

A solid supporter of stock Ford ignition systems is Performance Distributors in Memphis, Tennessee. Two types of Motorcraft Duraspark distributors are available from Performance Distributors. The basic Duraspark distributor offers a heavy-duty ignition module, high-energy
distributor cap, and custom curving applicable to your application. The DUI (Davis Unified Ignition) coil-in-cap distributor from Performance Distributors gives you the benefits of GM’s HEI ignition in a Ford-specific distributor. This custom-curved system eliminates the external ignition coil and steps up the power to your spark plugs.
On The Dyno…

Perhaps this is echoing what we’ve said in the beginning of this book, but engine projects have to follow a plan to be effective. Winging it as you go works — if you’re born lucky. For most of us who build engines, having a plan and following it with discipline is where power and reliability come from. When you’re on a budget like most of us are, compromises have to be made and common sense must prevail.

Like we said earlier, your engine’s mission has to be established before you get started. Street engines and racing engines have completely difference missions because power management is very different. On the street, you need a broad power band that begins with good low-end torque all the way up to high RPM freeway pursuit. You need a street engine that pulls well out of the hole and will make torque when it’s time to pass. For most engines, this power band spans 2500 to 5500 rpm.

For racing, your power band should be up high in the 4500 to 6500 rpm range in a budget racer. We do this because racing engines make their power up high, which keeps the power in place and ready. When we keep an engine in its power band, we keep it ready to meet and exceed the need. In high RPM ranges, racing engines make more power than they do in the best street engines. This is what an engine’s personality is all about. It is about making power and when.
Whenever you are planning an engine build-up, you want to know how much power your engine is going to make. We have compiled ten low- and medium-budget Ford V-8s and put them on the dyno to see how much bang can be achieved for the buck. None of these tests is a guarantee that you will achieve the same results. However, given good common-sense building technique and packaging, you can achieve similar success. Perhaps you can incorporate a few speed secrets of your own.

5.0L EFI (273 hp)
Westech Performance shows us what can be done with a 5.0L EFI small block for under $3,500. This is a medium-budget street small block with a stock bottom end. Aside from a .030-in. overbore and dynamic balancing, the short block is relatively stock. We infused power by topping this engine with Ford Racing GT-40 heads and induction. This is a modest fuel-injected street small block you can build for approximately $3500. What yo can expect from this engine is a slightly lumpy idle with crisp throttle response for good traffic light-to-traffic light performance.
Federal Mogul flattop forged-aluminum pistons give this engine 10.5:1 compression with 60cc chambers. Reconditioned C8OE connecting rods prove to us the 5.0L High Output engine is a solid mill from the factory. These rods can take extraordinary hammering again and again without failure. The Ford Racing E-303 camshaft is an aggressive hydraulic roller that gives this engine a slight lope to its idle. However, it remains a streetable mill for the daily commute. Cylinder heads and induction system are stock GT-40 pieces.

We learned on the dyno that this is a snappy mill that doesn’t have a temperamental attitude. On the open road with either a T-5 five-speed or Automatic Overdrive, you can expect 20-25 mpg in a Mustang if you’re using 3.55:1 gears.

On The Dyno...