Picked up a H.O. 5.0 the casting numbers on the heads were ETTE or E77E. I also seen 32 and I think AP or A9. does this mean anything. Also is there a place where i can see all the casting numbers for this 5.0. The motor also have crane roller rockers on it. But It looks like the ford oval is stamped on the rockers. i'm just getting into mustangs so forgive me if I sound a little juvenile.