Speedmaster heads for SBM

IMO, you’re over thinking it. But that’s OK.
I’d like to see the tests of a head to big for a 318 and a 2.02 valve. Also, as you said you have to spin it higher to get the full benefit of the head. That would apply to every head and cam set up on every engine and it applies to 99.99% of everyone with a car. The point .01 percent it doesn’t apply to are those that drag race and I’ll make the claim many racers do not take full advantage of the heads port ether.