Feather duster value

Ok so I'm new to these forums. Im looking at getting a 76 Feather Duster today with the 4 speed. I believe everything is original and there is minimal rust. Everything also appears to be there or at least almost everything, and the interior is in okay condition. The engine probably has around 300k miles on it and could probably use a rebuild and some tuning. My question is, what might be the value range of this car? It runs, does leak anything or smoke. Ive looked everywhere to try to find a price range but i can't.. I know not very many of them were made. Any info would be great! Thanks!