Here this should give you some perspective. THe purple car below is a 70 Dart Swinger my Dad built. It had a 318 4 barrrel column shift automatic, dual exhaust, and an 8 3/4 rear end. He sold it for $6500. The gold Dart was my 72 Dart and was an original survivor car, slant 6 column shift automatic (i added the hood scoops and rear stripe and changed the hub caps), with disk brakes and the interior was top notch and I sold it for $4500. By your description this guys is more than double what he should be asking for it. If you would like to see some under hood shots and interior shots for more reference let me know I have plenty.