How rare is this and what's it worth?

Hey ya'll, I've got a good lead on my dream car, a 67 Dart GT convertable with the 273 4bbl/4speed, red with black interior. I have to be "interveiwed" by the owner before he will even decide to sell or determine the selling price. I haven't seen the car yet, but I know its not running and in need of a full restoration, but is fairly solid body wise from what I've been told. How rare is this combo and what should I expect to pay for a car in this condition? How much would it be worth restored to original specs? Any info will be greatly appreciated.