I helped a customer restore a 63 fairline 500.. He had the engine rebuilt twenty years previous and never broke it in... (260).. It was a cute little thing with not much interchangeability it seems like... It ran fine, for whatever reason he wanted to take it back apart and I can't remember why. But we took the heads off and had them gone through again... I don't know if it was his paranoia or what but we did it... while in the meantime we rebuilt the 2 speed Ford O-matic...