Man, I would never retire a good engine for that. It's too easy to machine up a bushing to center the props!! I have even filled wooden prop holes with epoxy and re-center drilled them with great success. The clamping loads hold the prop; all you need do is center them.

Electric props even come with a bushing set, and at start up an electric motor has more violent torque than a comparable engine.

AV8TOR