Manifold change good idea?

Hi guys. I'm thinking of changing from a single plain M1 to an RPM air gap. Engine is a 360 30th over Speed Pro flat top pistons, Purple shaft 284 484 cam, Edelbrock heads prepped by Hughes engines, comp roller rockers, 750 dp. 727,83/4 4.10 gears 3200 stall. Car is street driven and has run 12.88 @105.6 mph. Opinions appreciated.