small block heads, 4027596 casting # any good??

A-BOMB360 said
flow to .450" becouse thats when the #'s nose over. X-heads flow right to .550" typical would be anyother LA head.

Can't agree with that mate - I had my factory as cast 596s with a 1.88 valve, they flowed to 202 cfm @ .500 @ 28"

Porting with a 1.96 took them to 231 @ .550

A 2.02 then took them to 243 @ .550

The porting wasn't a high dollar exercise , basically just paid for X # of hours. -

I guess each bench can be different though.....