906 or 452 which is best overall

OUTLAW said

I have been cleaning out my garage and storage sheds and pitching just about everything but mopar parts. I came across a complete 69 383 out of a roadrunner and a complete 74 440 out of a ????. The 383 looks like it had a million miles on it. But the 440 looks like it was just rebuilt. Bearings look new, cross hatch in cylinders look fresh, top of pistons were clean.
In another shed I found 2 sets of heads complete, one set are 906's and the other are 452's.

Now for my question, which are the better heads stone stock and which are the better heads ported? Also which heads came off which motor? I know there are a lot of variables but just a general opinion is what I am looking for.

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906 heads came on 383-440 engines from 1968-1970. 452 heads came out in 1976 on the 400-440 engines.

"stone stock" they are pretty much the same and variables in casting might give one or the other a slight edge at any time. Generally on our bench the 906 has a slight edge, 3-5 cfm at various lifts but not all lifts. Really for all practical purposes, call 'em even.

Ported is an entirely different matter. The 452 is a little easier to port for the beginner and get some flow increase. For all out the 906 is the best of the two. The 452 will top out about 305-310 cfm and the 906 has been made to flow 340+ cfm here in our shop.

Should it make any difference, I have been working on the factory iron heads with my dad since 1959 when I was 11 years old. See November 1959 Hot Rod magazine, HOT PROSPECTS PLYMOUTH'S NEW 361---The engine they said wouldn't run.