My 383 had the stock Iron 4bbl intake, then I switched to a Performer, then to a torker. Still run the torker on my 451. I never noticed any power loss or gain for that matter by switching intakes. Not on that motor. It was also a very low compression motor with the psi killing MP474 cam. Cranking psi was only 96-98. Still made 13.72 1/4 mile times with the 3.91's , 3000 stall and headers.

I'd just advance the Summit cam, Run the Torker and put in the 3.91's if you want to beat on it. Without tearing into the thing and getting the compression up with some quench, you'll most likely just be stirring the poop soup.

My 383 (attached picture) was a big mismatch of whatever I could find for cheap, the 4780 holley 800 probably was way too much but it ran fastest with that carb too. Intakes and carbs on big blocks are a one or two beer job so for now I'd just run what ya have.

Don