Thanks for all the replies.

Haven't selected heads yet but they will be standard port aluminum.
A few other build specs
Weiand t ram with twin 450 Holley's
640 ultradyne cam.
Steel fact 440 crank off set ground to 3.9 stroke and 2.2 journal.
I'm open to either 6.535 or 6.7 rod length

I'm sure I'll be under 600 hp

That's should give everyone a HP limit.

Sounds like Molnar are a good brand.

I used to care but....... things have changed