Does anyone know the stock compression height of a 1972 318 engine? How far is the piston below deck?

I need to know what gasket I need adn how much CR I would get with the stock EQ Heads (62cc) or if I should shave them to get a smaller volume to get even a higher CR...

Thank you

dont know the CH but when you find out this calculator is user friendly http://kb-silvolite.com/calc.php?

It takes a lot of shaving on the heads to even get 1/2 a point in compression. It would be cheaper and easier just to get a new set of higher compression pistons.

My brother just had the heads off his stock, 53k original mile, 1972 318 about a month ago. The below deck height of his pistons measured at 0.070", but I've read that a stock 318 can be as far as 0.090" in the hole.

Assuming 0.070" in the hole, if you just go to a 0.028" MP head gasket you would get 8.97:1 compression. For ever 1cc you remove from the chamber you will gain about 0.1 in compression ratio. What that translates into for how much you have to mill off your heads I don't know exactly, but it should be about 0.005-0.006". Thus to gain another half point in compression ratio you are going to need to remove about 0.030" from the heads.

Don't forget that the intake side on the head needs to be cut also to make the intake to head angle correct.

Yes you need to remove 0.0095" of the intake surface for every 0.010" you remove from the deck. So for 0.030" off the deck remove 0.0285" from the intake surface.

You will also need shorter push rods. The stock push rod length is about 7.500". (it varies a little) Here's the formula to figure out what length push rod you need;

Push Rod Length = 7.500 - Delta/cos(14)
Delta = amount milled + difference between old and new head gasket crush

This is assuming you don't change your cam and/or lifters, then you need to take the cam base circle and lifter length into account. If you are changing cam and lifters I recommend you get an adjustable push rod and a cheap 8" calipers from HF to determine what your push rod length needs to be.

silvolite replacements are 1.741 CH, sealed power replacements are 1.72", I'd guess it's somewhere around there....

thnx for the infos!!

0.070" is a lot! That will probably kill my quench effect, BUT I really don't want to touch the bottom end on this engine, I want a simply bolt-on 100HP or more upgrade on a really tight budget with a new set of heads, cam&lifters and intake/carb... no pistons, no machine-shop work (costs 2-3x more than all the parts together over here! Not even counting all the time I would have to spend for this)

So the thinnest gasket I found is 0.021" (copper) and from Mr. Gasket 0.028" (graphite) This will give as stated above up to 9.1 CR! With no quench I guess this is already very high isn't it?

And does anyone know if I can install 340 exhaust manifolds (71-73) on 318 heads? Someone told me that this works very poorly and I need to fabricate adapter plates since the ports don't match?!