I have a set of J heads with 68cc chambers, I need 62cc to reach the 10.4:1 compression I need. I already have a set of Cometic head gaskets .060" which I will use. Has anyone milled them that far?
Sooooooo about .030 to get to where you want to be. Then, I'd mill the intake side of the head for another batch of money. If it were me, I'd sell the gaskets and get thinner ones and be done.