Width of Dart frame rails and Duster Rails

The frame rails are supposed to have the same dimensions, at least within factory tolerances anyway.

That said, swapping parts from one modified vehicle to another has no guarantee's. Measure your rails and measure the perches on the axle, only way to know for sure.

I can measure my Dart and my Duster tomorrow since I've got both, but measuring your car and the perches would be the only way to know 100%. Unless you welded the perches on yourself, there's no guarantee they're even in the right place for the car they're on.