One of the last drag race motors I dyno tune in SO CA was a 440 block stroke to 3.91 stroke with a set of CNC ported B1-BS heads taken out to M.W. intake port size, they flowed right at 350 CFM at .700 on the intakes. The motor had a little over 12.0 to 1 compression and a M.W. port size tunnel ram with a pair of Holley 750 D.P. prepared by JET performance in SO CA and a old Crane custom ground solid roller cam, nothing all out race at all
We played with timing, valve lash, spark plug gap and heat range and finally treid a set of nine inch tall velocity stacks with a set of 11 inch diameter by three inch tall paper air filter elements on top of the stacks, George, the dyno operator, said that change will make the motor lose HP, it didn't It gained around 8 HP from the bottom RPM all the way up to the peak RPM, 7000 RPM
I'm a firm believer on all Holley D.P. that straightening the air flow up above those carbs. really help them run better