Done that a couple times: RB with an RPM, Holley on a GM heat baffle & 3" open-element air cleaner. Both times though I used a drop-base aircleaner bottom.
Re: 383 Edelbrock RPM under 1964 Plymouth hood - 07/19/1603:48 AM
I have a RPM on my 64 Belvedere with a 440 and ended up having to install a drop base air cleaner with a 2-1/2" filter to get the hood to close. The RPM is a pretty tall intake.