906 or 915 ?
I had a set of 906’s here this summer that had been done by a Mopar knowledgeable shop.
Retained the 2.08/1.74 valves.
Had their valve job and bowl blend.
Peaked at .500 on the intake, then dropped off as the valve was opened further.
That’s fairly typical for those heads without really going after the SSR(which was the situation with these).
A little less effort than what went into these 906’s would get you to 250@.500(and more at higher lifts) on a 346/902/452 head.