If you're going to sell the car, why bother spending the money on a new carb? You will not regain the investment. And the new owner may not like the carb you swap to. If it's working, leave it be and sell the car. A few years ago, I had a 77 F100 that I was selling. I had a Holley 500 cfm 2 bbl on it, but had switched it to an Autolite 2 bbl to sell the truck. The Autolite had hot start issues and the buyer noticed it. The Holley was fine and just to make the sale, I switched the Holley back on, but only at the insistence of the buyer and the fact that he was willing to fork over $50 extra for it (which was by the way, what I'd paid for the Holley, used from a StangNet member)