If my memory serves me, I remember that Tony aarcuda member was posting on here maybe a year or so ago that he was failing head gaskets in his 10 second car at 11:5 compression. He switched to cometics. The felpro is claimed reliable up to 12:1, but how many members are speculating there ratio. How many actually blueprinted it with Ccing and fluid and factored in the diameter of the gasket bore etc. I ordered a custom Ross piston at 12:1. Actual blueprinted
Ratio using the 1/2 inch down fill and allowing for gasket thickness and bore and Ccing one head chamber was 12.7, just sayin.