906 vs 452 heads on 440

I'm building a 440 10.35 compression with a mild cam.
If I had the choice between a 906 head and a 452 head what Would be better for 500 horsepower street application?

By the time you get a 906 or a 452 set of iron heads ready to make 500 horsepower, with a mild cam (or a radical cam for that matter), you could have bought set of better aluminum heads. Well, unless you own a head porting shop.