Has anyone ported stock magnum heads and have the before and after flow numbers .???

Member 63gt iirr did a thread on stock casting magnums. I did a stock flow test 15 yrs ago on a stock casting, 209 cfm iirr peak. The pinch controls the speed , floor especially or I should say the floor is drastically effected by its size.
LA heads when around 260 cfm it doesn't matter to knock it out, why? Because by then the port is so much bigger that the pinch even maxed is too small.
That's if you have your bowl venturi just right, smallish almost tons of radius by the plug side and chamber wall.
I believe from experiance two completely different shaped bowls will flow the same up to a certain point but one will carry a far greater flow at the top and hint so everywhere else a tinge