Stop in for a cup of coffee

just me, but why not
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.
That's what I'm thinking. They're $1000 before I port them and that's without valves and springs! I can get chinese heads loaded for $1000.