351 Cleveland Engine Mustangs, Shelby and Cobra Data

[Mach 1 Club]

351 Cleveland

The 351 Cleveland engine is one of the engines in the 335 FORD series of engines. Other engines in this series are the 351Cleveland Boss, 351 Cleveland HO, 351 M and the 400 series.

The C behind the engine denotes the place of manufacture - Cleveland, Ohio. As opposed to a 351 W where the "W" stands for Windsor, Canada its birthplace. Now to clarify the "M" located behind some of the 400 series engines. It does not stand for 'Modified" or "Michigan" as most people think. It is simply a suffix added to denote a different engine from the Cleveland and Windsor.

Some suffixes found on this engine family stand for performance options such as H.O. stands for High Output and CJ for Cobra jet. As a matter of fact, these engines were the result of Ford's quest for a bullet proof medium displacement high performance engine for use in the production vehicles. Alas the timing was poor as the gas prices rose and the fickle public went on to grossly underpowered vehicles that moved at a pace between slow and slower.

The 351 Cleveland engines used "canted" valves and large intake and huge exhaust valves for maximum breath ability. A canted valve is set in the heads at an angle, not vertically. Canted valves increase performance by allowing the heads to flow a higher ratio of gas and exhaust in and out of the heads than normal valve design. As a result, power is increased and fuel efficiency is also increased. Because of these characteristics, 351 C engines are very well known in both the NASCAR and Pro Stock Drag car circles. When driven in everyday traffic, they can be fuel efficient operating as an engine would if it in the 300 CID size.

The 335 series engines use a dry manifold configuration. In other words, no coolant flows through the manifold. At the front of the block, there is an integral timing chain cover, at the top left hand side, coolant enters the block through the thermostat and then part of it goes through the radiator and part of it goes through the water pump. At this point below the thermostat on 351 C engines is a brass diverter valve. This diverter looks small and unimportant but it is critical. Made of brass it looks like a brass freeze plug with a hole in it and is driven into a seat below the thermostat. If you have an engine you are going to hot tank, REMOVE THE DIVERTER VALVE. Hot tanking will eat the brass and no one makes these that I can find. Your engine will overheat without this valve. To remove the piece, you can generally pry it up from a small hole located below it. Or you can sometimes drill a small 1/8 inch hole off to one side and remove it with a slide hammer puller. Do not destroy this piece. If you feel lucky go to your Ford dealer and ask for part # D0AZ - 8K517-A.

351 C 4 bbl engines produced through 1971 and all 351 C 2 bbl engines use 2 bolt mains. All HO, Boss, CJ and 1972 - 73 engines use four bolt mains. However, all blocks are cast to accept 4 bolt mains and if you have a set of 4 bolt main caps, you just need to also have enough money to pay to have a machine shop drill out the block and tap it.

The Boss 351 had some differences from the other engines there are: it was fitted with a dual point vacuum advance distributor, it had a rev limiter that was almost immediately removed by the consumer because they did not want to be limited to the 6,050 - 6,150 RPMs that Ford set the device at. The engine was also the only one to receive solid and adjustable lifters. In 1971, the engine was fitted with an aluminum intake manifold. All other 351 engines got a cast iron version.

The 351 4 barrel engine was designed to breath, and breath it did. The intake ports are so big that the engine does not run efficiently until it gets to at very high RPM. In contrast, the 2 bbl engine had undersized ports and did not breath well at all. It had low end torque, but petered out at higher RPMs. I you are very lucky, there is an Australian version of the manifold that has intake ports that are not quite as large as the 4 bbl version but bigger than the 2 bbl version. I have never seen these heads, but have read about them in the past.

MORE DATA AND CHARTS HERE

[Kit Sullivan]

The 351 Cleveland engine was one of the most expensive engines to design and engineer by any manufacturer up to that point in time. Some sources claim that at the time it was the most expensive engine design program ever for a regular-production engine. There is no doubt that Ford was serious about building a true hi-tech (in its day) mass-produced performance engine.
What most don't realize is what the impetus for the development of this engine was in the first place.
It would be nice to think that Ford simply wanted to build an engine that would take thier performance-cars, such as the Torino and Mustang to the "next level".
The truth however is that in the world of beancounters and product development costs, neither the Mustang nor Torino, seperately or combined would ever be able to justify the enormous development costs this engine program required. It would never have been approved under only those circumstances.
However, as luck and history would have it, the reason the Cleveland engine program was given final approval was for no other primary reason than revenge by Henry Ford II on Enzo Ferrari for what HFII, as well as the rest of the motoring world saw as the ultimate insult and snub of Ford by Enzo.
Ford and Ferrari had been in negotiations for quite sometime concerning the planned sale of the Ferrari company to Ford.
The first hiccup was when Enzo reneged on the terms of the initial proposal and decided to sell only the street-car division of his company to Ford, and keep the Ferrari race division and programs in the Ferrari family. As talks broke down between the two volatile Italian car-makers, and Ferrari famously and publicly stated that "no Ferrari vehicle will ever wear a Ford logo", and unceremoniously called a complete halt to all negotitations
HFII was incensed and decided to publicly humiliate Ferrari by beating him at the one thing Ferrari held near and dear...his championship racing awards.
It is well known that Mr. Ford decided he was then going to go racing at Le Mans, an event basically "owned" by Ferrari's fabulous racing vehicles for many, many years.
The clandestinely-known "Crush Ferrari" Le Mans race program by Ford was given nearly unlimited funding and explicit permission to spend and do whatever it took to best, and humiliate Ferrari on his own turf.
We all know that is exactly what happened with Ford being the only American car manufacturer ever, even to this day, to win at Le Mans.
Once that goal was accomplished, Henry lost interest and along with some other changing influences the racing programs at Ford quickly dwindled, having fulfilled thier intended purpose.
But...Ford was not done with his now irrational dislike of Enzo and decided he was now going to further humiliate Ferrari with a street-driven and publicly-available product.
The plan was to produce an Italian-American hybrid sports car, one that had the heritage and cache of a craftsman-produced limited-scope exotic Italian car, combined with a crushingly powerful and sophisticated American drivetrain that only a huge corporation such as FoMoCo could afford to develop and produce.
After considering many Italian car makers, Ford turned to a small manufacturer that they already had a slim relationship with: Alejandro DeTomaso, the Argentinian maker of the lovely but finnicky DeTomaso Mangusta...a beautiful lithe gem of a car with a screaming little Ford 289 mid-mounted under its stylish glass engine covers. The thinking was that with the influence a large, succesful corporation like FoMoCo could supply, all the little manufacturing troubles and glitches inherent in low-production exotic cars could be ironed out.
Part of the arrangement was that Ford was allowed to purchase controlling interest in DeTomaso Automobili, a means to give Ford the control he wanted to have in the arrangement.
Ford designer/ stylist Tom Tjarda penned the exquisite shape of the new low-slung mid-engine 2-seater sports car, to be named "Panther".
At the same time the car's body and chassis were being developed over in Italy, the drivetrain program back in the USA had nearly unlimited funds to develip the ultimate mid-sized ultra high-performance V-8, with the caveat that this new engine would also be used in the more mainstream regular production Ford vehicles. A little bit of "trickle down" engineering to help the entire line.
Thus was born the infamous 351 Cleveland for the main purpose to further humiliate Enzo and his road-going Ferraris.
As we all know, the "Panther", ultimately renamed "Pantera" to emphasize its Italian heritage as much as to downplay any percieved association with the militant "Black Panthers" in the news at the time...was not the rousing success it could, or should have been.
A fabulous car for sure (and my absolute all-time favorite), it was rushed into production probably a year or two before it was really ready.
When a Pantera worked as intended, it was as intoxicating as any exotic Italian supermodel could be. But...when they broke down, which was frequent, they were as aggravating as the most temperamental high-maintenance beauty could be.
Shoddy wiring, poorly designed cooling systems, An A/C system which apparently had the sole function of heating the incoming air, and transmission woes from the start. This car had a huge appetite for U-joints.

Too bad the Pantera was not all it could have been. I bought a bright yellow chrome-bumperette version '72 "S" from my brother-in-law in '79, and boy was I in love! That is one car that is beautiful from every concievable viewing angle...its stunning good looks can only be improved by seeing one in motion. Reminds me of a big jungle cat stalking it's prey. Maybe the name "Pantera" is putting that image in my mind, but it is gorgeous nonetheless.
The honeymoon with that car was quickly over for me though: Cramped with no place to put your feet ( I used to like to wear cowboy boots in those days), hard to drive, hard to see out of, electrical gremlins, overheating for no apparent reason, body parts randomly falling off...I had that car for 5 years and it nearly broke me. I sold it at a nice profit, but I still miss the sound of that exhaust...

Sorry about the long post, but I love those cars and the Cleveland.

[Steven Harris]

Mach 1 Club - the extra data and charts at the end of your article are a great source - thank you.

Kit - what a great personal story and extra on the history of why we all have the 351C to enjoy.