Rear Axle Position.

did that work out ?

Yes/No. It'll work on my buddy's original 340 duster, but not on the same year Dart Swinger. There was over a 3.5 inch difference in clearance between the 8.75 in the duster and the duster's gas tank vs the 8.75 in the dart and it's gas tank. The only thing I could think of is the wheel base of the duster being 108 inches vs that of the 111 inches of the dart swinger.