How Much Can Heads Improve Compression???

Krooser said
Machine the block to achieve a 'zero' deck and use a thinner head gasket. Unless you have about 9.5 or higher compression ratio leave those aftermarket cams in the box they won't help.

You may want to find a pair of 302/308 heads from an 80's 318. Mill 'em down. They have smaller swirl combustion chambers.

I have a set of 360 J heads that have been angle milled and, with a flat top piston, we figure the compression will be around 12-1 which is just right for the engine we are building.

The point that I'm trying to do here is not to do any more work to the short block, it's been freshly rebuilt many years ago. I'm just going to check the torque on all the crank and rod bolts and try not to disassemble the short block. The short block is fresh and ready to go, I don't want to throw away money on upgrades.

The gaskets that come in the rebuild kits are .065" thick and a little too much. We also ordered and now have a set of .040" head gaskets, which will take about 4 cc's out for us.

I want to see if I can get close to 9.0 with just changing the gaskets and using the heads that I have available now.

The 67 heads look promising with their small combustion chambers...

We will be picking the cam later after we figure out which heads we are going to use. I do have some "mild" street cams that may be ok. I don't want anything too big if I don't have enough compression to back it up.... I'm thinking around 268° duration range.

Then I have to mock it up and check the piston to valve clearance....

Then assemble the engine and drop it in... :burnout: