360 compression and cam questions

I'm pretty sure the gasket bore is 340 sized witha .060 overbore. That's the largest possible factory oversize. 4.04 + .060...meaning 4.1.
I agree most open chamber heads regardless of casting have much bigger than claimed size. Add to that re-using factory valve sizes and a valve job, and that grows. Most I see are in the 72-74cc range. Using 73ccs and the 4.10 gasket I get 9.:1. Still fine IMO.