In fact, the RPM is not well-suited to the 350 Pontiac. Performer is much better. RPM is the "red-headed stepchild" of Edelbrock intakes for Pontiac. The 400 is about the only engine size that really benefits from it. The runners are too large for the smaller bore 350, and the low-end "rush" is too much with the longer strokes. This is one of the many differences in how to approach a Pontiac versus a small or big Chevy.
Conversely, Performer is no better than the cast intakes Pontiac put on there in '69, as Bill and Lynn have pointed out. But the factory intake requires the use of Q-Jet or a really good "spread bore". Adapters on these intakes are verboten. Performer will work well with your 650 E-carb.
It would be really helpful if you elaborate on the cam. "Mild" is not a good description. Numbers, please.
350 Chevy will rev to the moon. 350 Pontiac makes significantly more torque at lower RPM. 350 Pontiac is not a good revver. That's what 400s are for... (:-