If you insist on the procomp heads... scrap all the parts that come in them and have a reputable machine shop go completely through them and outfit with decent parts. Not enough info on the cam to really give an opinion. Porting will offer what you are willing to put into them... a half-assed job will net so-so results... a decent job and actually fix the runner locations from core shift can net 50hp or better without going full blown race porting. 650-675hp is attainable on a pump gas 496... and ypu can do it with those heads... just need to sort out your combination and plan.
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