Taking my 340 to Caroline Engine for rebuild

I would pull the heads and pan and leave the short block together. The buyer could then see the bores and could pop off a few caps on the crank to check the journals.
I agree, if you do a proper rebuild its a money loosing proposition. Even then its a hard sell because most people wont trust the rebuild done by someone else....I know I wouldnt.
You might want to post the vin number to see if you can find the owner of the car it goes to. That is unless you know the car does not exist anymore.