So unless I get an open chamber aluminum head I have to have a custom thicker gasket. Like the 340s of old my Pistons protrude .010 above the deck and I need to either have open chamber heads and or a pretty thick gasket. The machine shop that put my motor together originally countersunk gasket matched my head's like .040 and you don't really even notice it. Just to make sure nothing touched. I used a felpro 1008 when I had them off as they did when they originally put it together. They wanted a bare minimum of thirty thousandths plus the .010 out of the hole and and the 1008 compressing to .039 it was just too close. That's why they countersunk a bit...