Chevy 302 questions

[jeepracer]

hi, im looking to build a 302 chevy. i figured id ask a couple of questions befor i start buying parts. im looking to get as much h.p. out of it as i can. my question is, will stock 2.02 1.60 heads flow enough on a 302 to produce 500+ hp? i plan to get an aftermarket forged crank. aftermarket dome pistons. aftermarket rods. chevy 4 bolt main 350. and a roller cam. not sure what size the cam would have to be, if these heads would work. other option is to buy aftermarket heads and do anything to them. the reason id like to keep the heads stock is limiting factors for our classing. if i were to go aftermarket heads, how much hp could i get?