Advice on Cylinder Head cfm for 340 stroker

Check deeply into the Brodix heads.

Generally speaking, more cfm the merry. Best to have a fat curve. The best earliest flow possible.

Who is doing the CNC work on the Pro Maxx heads?
Can you list there flow spec sheet?
The Promaxx CNC heads are an in house option of theirs. Flow specs on their website. I'll see if I can get em posted here.