Originally Posted by clevo
I've just pulled my 2v open chamber heads off my 351. The compression with these heads was 150psi, my cam is, I think standard.
I have some 2v closed chamber heads that I have ported and cleaned up, what will the likely compression be? Will it be too high? bearing in mind I am using LPG. I have flat top pistons .30
If the compression is too high what is a suitable LPG cam that has overlap to reduce compression ( I don't want a ping!)
Also how much extra power should I gain with these heads?
It'd be at least 11:1 but if your running zero deck height (piston level with the top of the block)? You'd run around 13:1.
From the factory clevo's don't run zero deck height.
I threw some 302 closed chamber heads on a stock 351. Had no issues running pump fuel.
150psi is about 8.9:1. 185psi = 9.5:1 etc So 11:1 would be about 200-210psi.
Remember cam affectes the compression. You can have 150psi stock cam put in a large cam and have the compression drop by 20psi!