go google it it was production they had to, even back then, to race it it had to be production, I personaly did not live in those days but being from detroit I know where there are three I have personally seen and several engines under numerous benches (seriously) I'm not BS'ing the guy's I know are quite aged now but growing up I heard plenty of story's ford would cater to local drag racers in detroit hooking them up to win at the strip parts to upgrade the already insane fast for the time 427's just to slam mopar in highland park michigan,and they did ford actually get this rated that bad 427 at "410" horses they loved to play around the actual 616.