The value of the car would depend on a many variables that aren't really reflected in the NADA guide. The big one is which motor,carb, tranny the car came with originally. The fluctuation in value isn't nearly as extreme for a coupe as it would be for a convertible or fastback, but it still makes a big difference. If your car originally came with the 'U' code 170cid six cylinder and a three-speed manual tranny, that will be a hard car to move unless the body is basically all original and solid as a rock. If it's an F code 260 2bbl V8 with an automatic, it will still need to be veeeery solid, but it is at least sellable. The D code 289 4bbl with a four-speed manual would be much better and a K code would be best of all. If you could tell us a little more about the car, like the first 5 digits of the vin, and possibly post a couple of pictures of the car, and take a look underneath the car and see how much rust there is and how much rust repair has been done to the car, that would help out on figuring out how the car is actually worth. Good luck.