Match this 500hp/500lb-ft Combo?
There’s obviously no problem getting 500HP from reworked stock heads on a 4” stroke combo.
It’s just whether one wants to spend the $$$ to end up with a no quench iron headed combo.
There are at least 100 ways to get the job done, and all of them are fine as long as the owner is happy with the result.
I would take what I perceive to be the path of least resistance...... and that path has TF heads.