63,64,65 273 heads

i was told they changed heads in 65 -66 do rockers work in all years , did they move valves i know they changed the trannys in 66 , but never heard about heads or motors any in fo would help alot of people i think 65 heads dropps on a 67 can any 1 tell me diff or did i get bad info

hi, the 64 to 65 heads have smaller (5/16) bolts and different angle , compared to 66 and up, which are (3/8), different angle. all rockers will swap out, intakes have to match the head years for bolt up.valves are all same size and location. just food for thought.