Best cylinder heads

915 is best cost more than aluminum heads all rebuilt, 906 heads cost more than others because they were during the higher hp era.
If you're looking for flow numbers on a factory iron heads, none of them are outstanding.
So whatever you want to buy will work. If u want to port them they can end up flowing all the same.
Don't get obviously the RV 413 heads.
Gasket match the intake ports and clean up the bowl, there's usually alot of flow to be gained in the bowls, everyone bowl I've ever seen looked like a dinosaur took a dump in it. But that's not just mopar