LD340 v/s Edelbrock Air Gap

John may be able to speak better to this but the LD340 has large volume runners compared to the RPM.
I suspect the narrower cross section of the RPM runners better maintains velocity under low flow (low to mid rpm and part throttle) situation. FWIW it has been reported that the RPM made for brand C favors certain runners at high rpm.

I have an RPM to try out instead of the LD340 but never get around to actually doing it....