I applaud you taking the initiative in rebuilding the 261.
As far as building it to sell it, you probably won't come out ahead. The machine work will eat up all of your lunch money (beer funds depending on your age group).
If I were in the market for a rebuilt 261, I would not pay any where near top dollar for one which wasn't rebuilt by a reputable professional engine rebuilder.
Welcome to the Bolt, BTW.
Carl

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission