How can I tell if my 64 Starfire has the original engine?
Is there a number stamped on the engine somewhere that will tell me if the engine is original to my car?

 

Look on the left head, at the center between the valve cover and the plugs. There's an engine number there. If it has a J prefix and S suffix on that number, odds are it's the original engine. Other than that, hard to determine. Olds didn't start putting VIN derivatives on the engine until 1968.

'Course if car has ever had head work, all bets are off. Look in same location on the right head just in case they got switched sometime or other.