Its likely that the 347 wont add much if any money to the price. I think you'd be loosing out. Put it for sale as is, then also say you have a 347 engine for sale too and give them a package deal if interested in both. I wouldnt put a new engine in, you'd waste lots of time and energy and you wouldnt get paid for it
I wouldn't offer the motor as a "package" deal because you'd get hosed. If the guy is interested in the motor, tell him how much you want for that, too.
Also, if the block is bored 0.30 over, it's not gonna run.