When most people spend some coin on a car, they like to be able to test drive it first. That usually seals the deal. If they like how the car drives, and how the engine responds, it speaks to their emotions.
Best bet would be to drop a motor in that car, get it fully operational, and then try to sell it. Motor prices can vary from $500 to $4k depending on when it was built, etc.
'68 Firebird, 350-4, 2 spd auto, triple black, Dlx Interior
