I have a 1975 F100 Ranger XLT 2wd SWB originally had a 390 but now has a 429 out of an early 70s LTD it is bored .030 over.........I put new pushrods and rocker arms in it only to find out a valve is stuck(snapped pushrod in half) and I'm not sure if the heads have to be rebuilt or not but i'd rather get some boss 429 heads if they'll work?