906 Head shop

In my experience, the numbers you posted have never, ever been verifiably achieved with a 2.08 valve. Not by anyone I've ever spoken to or read about, anywhere. Even professional (well respected) iron head porters can't touch within 20cfm of your results with a 2.14 valve. No disrespect intended, but something isn't right. I dont run 2.08s. But typically I can get 250-260 at .500 with a back cut 2.14intake valve, a clay radius, and a 4.25 test bore. The performance of the car backed up these numbers. As I've said, I do not test my own heads and dont test every set. But that's my experience anyway.