Smaller primaries are only better because the factory ports are junk.

Open the ports.

Outflow SD's and create an obstruction in the exhaust flow. Stock valvetrain also blows. Upgrade that. INcrease flow.

Thus, Pacesetter's and TOG X's come into play.

Regardless, flow will still be slightly better up top with the larger primaries IMO.

I have no evidence. Just, I told you so.