If you are going to rebuild properly like a complete rebuild, new paint, etc. and then sell. I think it would be a waste of money. Like unless someone is willing to pay top dollar for that engine rebuild I would just get it running and sell as is. Why would you put all that time and money(probably more time than money) into an engine you are not going to keep? That is just my opinion though. But it would be a very good learning experience to rebuild an engine.