Without more information, there's no way anyone can place a value on it. You would need to post pictures of the car and pictures of the documents before we could even start to venture a guess. Right now, 1968 Camaro Rally Sports go from a few thousand to the upper 30's to low 40's depending on condition, documentation, options, etc... 1968 Z28's are going for probably double that, but again, it depends on condition, documentation, options, and if it's numbers matching or not. If I were to throw out a number, I'd guess a non-numbers matching Rally Sport in fair to good condition would probably be worth around $10k to $20k.
Ed