Edelbrock LD340 Intake Manifold Usable Max RPM?
The runner length decides the rpm its tuned for but doesn't mean it won't rev/make power passed the tuned rpm range it just loses ram effect but there is higher rpm bands that get a lesser secondary ram effect. Darin Morgan was talking about tuning the headers above intake tuning to extend the power range. But cross section/plenum volume will limit max rpm if velocities get to high it will choke it out.
Richard Holdener did some test with runner length and found out above tune it could still rev but power just flatten out.