Here is one to make a offer on says it needs rebuilt and has free shipping
https://www.ebay.com/itm/187875841865?chn=ps&google_free_listing_action=view_item
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...