OK this is a long shot, but there’s very little reference material on the construction of this car, I don’t know what rear suspension was under the car, coil overs, or leaf springs. Car Craft magazine article on Sox and Martins 72 Duster shows leaf springs, the Sox and Martin built Herb McCandlees Demon shows Coil overs, but it’s a restored car, and may not be the original rendition of the 72 car. the Mopar Missle 72 Duster was also coil overs. Does anyone have any info that might help? The front suspension had to remain Stock to the vehicle, but the torsion bars were swapped for coil overs between the stock control arms, and Pinto Rack and pinion steering added.