why J heads, why not x heads?????

christineman said
ive got a set of heads on a 360, there cast no is 4027569 I believe,,, what if I just put 202s in them? can this be done and will they be as good as the factory J 202s?

I think you mean casting number 4027596..and those are "smog" heads i wouldn't put any money into those...