Sadie,
If you are talking about the bike you posted pics of in March, with engine number PC50153, it is most definitely NOT a BSA. It is a c1959 Indian Chief, as made by Royal Enfield in England, for the Indian Sales Corporation. Always hard to put a price on an item you haven't seen in the metal, but based on other sales over the last year or two of the same model in similar condition, I would think you could reasonably ask for at least $2500, possibly more. If your box of parts includes a Stewart Warner speedo in reasonable condition to go with the correct dash panel you have, up the price about 300 bucks. Or, put it on Ebay and see what happens.