What pistons and rods are in the current short block?
600hp from a stock stroke 440 isn’t that hard, but it’s not really a “slap something together” deal either.
Porting your current heads wil get you there.
You’d have to weigh that cost wise vs selling those heads and just buying some TF 240’s.
You’ll want a better bottom end than ly rods and TRW L2355’s.
Imo, instead of getting hung up on HP numbers, a better approach would be to come up with an ET goal.
As an example........With a set of 300cfm RPM heads I made 650hp from a stock stroke 440 with a flat tappet cam....... but it was a high CR bracket race motor.
10.0’s @3470lbs.
Knock a couple points of compression out of it, use a little smaller cam........ it would be in that 600hp range.
If a stroker and new heads are in the budget(just sell your current motor complete)........ then the same level of effort build as a 600hp street/strip 440, but applied to something like a 505, will put you in the 650-700hp range pretty easily.
