I think on turbo type applications, the head is overvalued.
I know a guy who has run 4.70’s in a Dart( think it’s a 71) with just B1BA heads, which are nowhere near as good as these are.
He I believe this year debuted a W8 turbo deal. Not sure what is has run, but my guess is that it isn’t a whole ton quicker.
Big hole, somewhat smaller hole, your still force squeezing air through it big time. How hard you squeeze to me, is more important than the size of the hole, within reason.