Honestly, I don’t think Stage 2 will get you where you want to be, not close. Unless you run nitrous or forced induction. Both viable options.
For me, my Procharged 408 uses well ported Hughes Edelbrocks to make 650 HP and 600 lb/ft. With a hotter cam and above 9.5:1 compression and it would be 500+ n/a.
My 4” 340 uses IMM ported Edelbrocks to make 511 hp.
See the pattern? The answer for you is clear.
Also, not required, is intake. You would be better served by a Victor EFI intake. Single plane will aid not hinder in the quest for 500 hp.