Stock Cam Specs - 69 351w 4v ?
#21
I don't know the specs on the stock cam. At 0.050" tappet lift I'd expect the duration to be in the 190 to 205 degrees. Also, a lobe separation angle of 114 degrees or more.

If you're now thinking hydraulic roller, it can be expensive. The lifters are the biggest expense. But on the positive side, because of how the cam lobes are designed, a more aggressive cam can be used and still maintain smoother idle and more vacuum at idle than a hydraulic flat tappet cam.

There are basically two method to convert these older 351W motors to hydraulic roller. 1) use OEM style hydraulic roller lifters and associated retainers and a retrofit cam which has small base circle cam lobes to compensate for the longer lifter. Or 2) the preferred method is to use the retrofit type lifters. These are the style with a tie bar connecting a pair of lifters together. Then use any standard hydraulic roller cam. Apparently, the retrofit type hydraulic roller cams (i.e. small base circle lobes) do not work as well as their standard counterparts.

Regards,
Mike
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#22
That what a Lunati grind but not voodoo series. He said it was a custom cam. I don't mind spending a couple of hundred more since I'm saving a ton doing it myself. What I don't understand is how the cam adds more lift without causing the valve to smash the pistons. Is there a limit to how much lift I can add before the valves hit the pistons hard?
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#23
Yes there is a limit to how much valve lift an engine can have before a valve contacts a piston. Some factors that limit valve lift:
1) Piston to valve clearance. Most flat top pistons have valve notches for clearance. Dished pistons (for lower compression) often don't need additional valve notches. Valve timing (when the valves open and close with respect to piston location) also determines piston to valve clearance.
2) Coil bind on the valve springs. A coil spring will only compress so far before the individual coils stack on top of each other. A total of 0.060" minimum clearance between coils is recommended to prevent any possibly valve spring coil bind.
3) The valve spring retainer contacting the top of the valve seal as the valve opens. Again, 0.060" minimum clearance is recommended.

Believe it or not it is usually items 2 and 3 above that limit the amount of valve lift. Included with all the valve spring specs will be the coil bind height. Part of selecting valve springs is to make certain the valve spring installed height - valve lift - 0.060 = the coil bind height or greater. Then there is making certain the spring loads are correct at the installed height and when the valve is open. Don't worry, it's easier than it might sound.

I can say, for example, on my 1969 351W cylinder heads, with flat top pistons with valve notches, and the valve spring installed height at 1.82", I have no issues with a valve lift of 0.542".

Before purchasing a cam and appropriate springs, etc. its a good to know what the current valve spring installed height is. It will help with selecting a new spring that is a drop in replacement. That is unless you plan to have any required machine work done to fit a new valve spring. My thought is its better to get a spring that's a drop in replacement instead a machining valve guides and spring seats to accommodate a new spring.

Regards,
Mike
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#24
Mike should i replace the distributor gear with a bronze gear or should i go buy NOS?
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#25
Bronze gear is not recommended on a street car. They tend to wear faster than cast iron or steel. If you select a hydraulic roller cam you will probably need to install a steel gear on the distributor. Be certain to ask the cam manufacturer. Flat tappet cams use a cast iron distributor gear which your stock distributor already has.

Let us know if you plan to replace the distributor gear. The location on the shaft is very critical. You DO NOT simply line up the roll pin hole on the gear and shaft. Dangers if the gear is improperly installed are (1) distributor is damaged (best case scenario), (2) cam is damaged, and worst case scenario is (3) the engine block is damaged to the point it can no longer be used.

Here is a link to Ford Racing's instructions. http://www.fordracingparts.com/download/...lation.pdf

Regards,
Mike
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#26
That's some pretty cool info on the distributor gear and how critical the end play "can be" to the whole thing. I swapped distributors back and forth in different Fords for years, guess I was lucky, but it was always Ford to Ford parts. I never tried using or swapping aftermarket distributors. I never really had any problem. I know with the introduction of Roller cams in the 85 up Ford, you couldn't swap the gears around. But I have moved one gear off one distributor to another to keep the gear that matched the cam being used, and never had a problem either? I've heard of others that had nightmares over this. Good info as this is something no one ever really thinks about. JTS 71 Mach1
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#27
Swapping complete distributors is not a problem unless there the one being installed wasn't assembled correctly. Taking a gear off then reinstalling it in the same location is also not a problem. Often, new gears will have the roll pin hole predrilled or partially drilled. The hole locations are random so it's important to press the gear onto the distributor shaft to the correct location first. Then drill (or finish drilling) the new roll pin hole through the gear and the shaft with it assembled.

Those Ford Racing instructions apply to small block Fords, 260, 289, 302, 351W motors. Maybe others as well, I don't know.

Regards,
Mike
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#28
I can find NOS gears on ebay so I'll take your advise and stick with stock.
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#29
The distributor doesn't have to be NOS. MSD, Crane, and others offer good cast iron or steel distributor gears. Summit racing offers distributor gears in their own house brand. The distributor simply needs to be made from the correct material for the cam, cast iron or steel. Double check with the cam manufacturer but its typically like this.

I've seen some new aftermarket distributors advertised with a gear (not bronze) that is compatible with both cast iron or steel cams. I'm not familiar with that material.

Let us know what you decide.

Regards,
Mike
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#30
Mike do you know size of distributor gear on 69 mach? would this fit?

http://shop.advanceautoparts.com/p/msd-i...butor+gear
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