If the numbers match between the engine and trans maybe 1200 (assuming 4bbl)? If its being sold as a core maybe 750? depends on where you are located too. The big thing with 340's if it would be sold as "rebuilable" is if it is standard bore or not and if any of the holes have been sleeved. That, I expect, would be the 2nd thing asked about the engine after the numbers matching question (at least that is what happens whenever I see a 340 for sale on moparts). If it is a 71 motor, it might be worth more (I think the carb is an oddball that year)