Milling 318 Heads to raise CR

For every .0095 off the deck remove .0125 off the intake side of the heads. .005 will reduce the chamber 1 cc. This engine should be 9.0:1 from the factory, using a Mopar Performance thin gasket will give you about .5 in compression gain. .030 is the max you can remove before you have to run shims or adjustable rockers. So if you cut .030 from the deck then you will need to remove .038 from the intake side of the heads.

But what I found is that you can cut .020 and not take anything off the intake side and the intake will still bolt up and you won't have any issues. So I would suggest that you cut .030 and cut .020 from the intake side of the heads, this way you'll leave more material for the valve cover gasket to seat on.