I dont think the stock 4 barrel intakes are too great, maybe theyre decent in comparison to an old school Offy or a crappy Weiand or something, but the RPM is a far better intake. Its been proven on the dyno and at the track. Even on a stock 383 I'd bet its worth 20 horse.

Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street