The parts you have are not "max performance" anymore. That might have been a max performance build in 1975, but it isn't today. Just call it "old school" and roll with it. Sounds like you have all the parts except for the cam. PRH can get you the best cam for the combination so talk to him. If this is drag race only with open headers then the cam can be fairly radical. Cast iron heads are pretty crappy in terms of flow so those old engines had a ton of cam duration. Old engines need completely different cams than newer engines with Trick Flow or Indy heads so you need to talk to someone like PRH who understands the difference. I'm not sure that you can make 600 hp with your existing heads. A good set of NHRA legal heads will make that kind of power but those heads are super expensive. You'll just have to put the combo together and find out how good it is. Nobody on here will know anything about it since we have no idea how well the heads have been ported.