what would be a good choice of exhaust to replace my stock gill on my 500 hp carb motors making around 575 hp. running 741 crane cams so reversion can be a problem as well. any real Hp gains to get over my stock gill.

Thanks

CMI E Tops, but I doubt you'd see any major gains because of them. Probably 10-20hp at most.
I saw ZERO gain in performance going from merc Gils to CMI Unitops on my 525SC.

so then i might as well just use my gill then.

I used the stock Gils on my blower motor with and w/o the blower running the 741 cam. Silient choice also. Never had any reversion issues.

I would. I just don't think its worth the extra $$$ for the possible 0-20hp gain.