How'd this end up working out? Sorry to pull up a really old thread, but I'm curious on outcome.

I put 731's in 450 HP 502's and really seen a big difference.. I didn't do any dyno pulls so I really don't know how they changed the engine's specs..

I wouldn't expect huge gains going from a HP500 Roller cam to a 525EFI cam. It should pick up a little bit, maybe 100-200RPM at wot throttle. You'd probably wanna be spinning the engine a little faster than the 5200RPM redline on the HP500. Engines would probably make around 500-525HP on a dyno with the 525cam.. Switching to a decent set of aftermarket heads, 600HP is realistic, the stock GM heads are the limiting factor.

With the 525 cam on a blue printed true 9:1 502 it made 560hp after a change in carb jets