mike, first off, check to see what type of heads you got, open or closed chamber, because depending on what you have, you may or may not be able to switch heads. i have a 396 with open chamber heads, but my pistons are made for closed chamber,(so i can have a higher compression ratio). now this can be done, but for some reason, you cannot run open chamber pistons with closed chamber heads. i believe it has something to do with the top of the piston hitting the head. so this is one thing you got to look out for.