GM parts are more accessible and there vehicles are good if you pick the right one Older is usually better new vehicles are problematic so any older truck you find with lower mileage is good and easier to work on you just have to search to find what you need
This is what i found:
The rear axle spring perch spacing (center-to-center) for a 1972 Dodge D100 (2WD) is approximately
43 to 43.25 inches.
Key 1972 D100 Rear Axle Details:
Perch Spacing: ~43.25" center-to-center.
Axle Type: Commonly equipped with the Chrysler 8.75" rear differential, which...
11 No ignition reference signal detected during cranking (bad Hall effect) OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor. Can cause the engine to stop working entirely with no limp-home mode.
12 Battery or computer recently disconnected
13*...