[b-man]

Bad idea.

Established shops that can offer some kind of warranty are reasonably able to turn a profit on rebuilt engines.

Private individuals doing the same are going to have a tough time getting their money back let alone make money selling a rebuilt engine.

People can’t trust the quality of the work or of the parts used in a rebuilt engine from someone with no reputation in the business and will only pay a low price because they’re taking a chance. No profit or very little.

You didn’t state exactly what engine you’re planning on selling.

350 engines running or as cores have almost zero interest for buyers. 400, 428 and 455 engines definitely will, cores for these engines are good sellers. But again almost nobody trusts an amateur rebuild no matter what receipts you can show.