it is my understanding I could be wrong but the sohc/dohc 427's the dohc was used on cars like the gt 40, road racers.and such while the sohc was primarily a street engine I could be wrong but that was my understanding also ford did put it in a galaxie 63,1/2 model with fiberglass fenders hood trunk lid and possible door skins extremely fast it had a plate on the dash stating this is a high perf vehicle intended for racing. it was a factory production car put out by ford.