Besides what Topside noted: condition of the grilles, front bumper fillers, trunk lid, fenders, hood and rear bumper are all critical. These items are more scarce than an equivalent 1970 Road Runner (maybe not the trunk lid..). Grilles are reproduced and good, but costly. The reproduction fillers are junk. Fenders and hood are very hard and costly to locate good replacements. Rear bumpers are very hard to locate as well. These components will drive the value even more so than usual, IMO. Without pictures, considering what's been stated here, I'd say 15-19k if solid and complete.