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?!