My home inspection of Speedmaster heads

I was sitting here feeling pleased with myself for finding a piston that gave me what I wanted for DCR and allowed me to run a thin enough gasket to get good quench clearance, and I realized that I had done all my math on the supposed 68cc chamber sized.

Unfortunately, I'd feel better if SM didn't give two different chamber sizes, 65 and 68cc, depending on if you got CNC porting or not, but they only do chamber work on the bare cnc heads, the assembled ones have as cast. Worse, the edelbrocks they're based on are supposed to be 63cc.

Here's the question...Has anyone CC'd the chambers on any of the SM heads?