Small Block Weiand Action+ vs. Edelbrock RPM Air Gap ET/MPH Comparo
Probably another .05-.10 in it once you get the jetting set. FWIW in the land of inter web misinformation, I’ve read that milling the plenum divider 1/3 of an inch from the floor, putting a one inch open spacer on and port matching a performer RPM is worth around 14 average hp from 3000 on up at the crank on the dyno. I myself would be weary about doing any more than that without a flow bench, Edelbrock actually did put a monumental level of R&D into those intakes. With the vehicle weight and wind resistance, I would think that a short height super sucker would be better than an open spacer. I trust a dragstrip a lot more than a dyno.