JoePorting wrote:As pdq67 suggested, if you have a 74cc head on a 355 with flat top pistons, you'll end up with around 9:1 compression (.040" head to piston clearance). If you have 11:1 pistons in there, you should be around the 9.75:1 area. I'd recheck my compression figures unless you are running 12:1 pistons.
Okay, now I'm starting to question the heads chamber volumes, I'm going on George's recollection there, it's been about 18 months. I do know I calculated the compression at about 10.2:1 with flat tops & .040 P-H cearance.
I'll describe what I remember about the heads and maybe some of you Chevy guys can decipher what they are, I remember George said they were common truck heads, the same as on his Blazer. I recall the four center bolt holes were horrizontal rather than at an angle like the rest. The intake ports had a weird shape at the opening and the rockers were self alligning.