I got my 383 built again and it is running great and strong. This engine is bored .040, 5.7 rods with sealed power 0.125 domes, 76 cc heads with a comp 292 cam. It was supposed to be 10.5:1 with these pistons but a machinest told me I was running around 12:1 and would need to run 110 octane fuel. All the math I have done, I still come up with 10.5:1 with a .035 head gasket but I ran a compression test on one of the holes and it was 205 psi. I'm not sure but 205 psi seems kinda steep for a 10.5:1. What are your thoughts??

Kodiak