It's my understanding that a mild build with stock cast iron heads as the topic of this thread seems to indicate, the performance advantage of the Performer RPM intake may not be fully utilized until one moves up to aluminum heads.

That said, pick the intake that will allow you to run at least a 3" x 14" inch air filter without a drop base and still have adequate hood clearance. If you cannot achieve this, any incremental gain with a taller intake might be compromised with your limited air filter choices.

See Engine Master Air Filter Shootout: https://youtu.be/EkpsydS8JXI