what would it take to make 450/500hp

I have a 30 340 block now freash hone job and cam bearings/freeze plugs.now I have bme pistons on eagle h beams should be about 11.51 comp with 68 cc heads that has a slight port job and clean up flow 240@500/140@500 I have 15/8 headers and a set of 17/8 headers also I have 950 hp carb 727 trans and 5000 verta dynamic and 4.86 gears with 27 tall qtp car is a 70 duster thats 3200 with me in it......give me some input on the build for the req. hp cam was a comp cam 306 mag 555/555 ........with the head flow and comp what would you install cam wise??????:glasses6::dink: