I with Hammer those heads would be peanut ports on a 632! Even with some serious massaging they still wouldn't flow no where near what that motor would require.
I was thinking of going with some bb2x's on my 496ci motor which would have been just about perfect, but found a deal on some merlin vr345's instead.
I've alwasy heard that you can race dyno's or flow benches either.
Charles