Really don't take much to get some muscle out of a 360 without spinning the H out it. I was running a 3000lb Duster consistant 11.70's with .040 over KB107's, Crower 485/495 cam, LD340 intake, Unported ub gasket matched heads milled to about 60cc's with 1.88 valves. Tried a set of 2.02 heads (after being told all things equal there would be little or no change of even go backwards a possibility). No porting but matched the CC's to the 1.88 heads. ran a full season + and found no change in MPH or ET. Oh by the way it is stock external untouched balance with used rods off a back storage shelf and a couple off a circle track engine.
Bottom end the same today, but with a Hughes cam and Hughes stage 1 heads. Runs 11.40's at the home track.
Doesn't see over 6000 RPM's