Is the truck going to used to do a lot of towing? Or hauling heavy loads?
Your pics show what looks like Dana 60 rears. Very common in 3/4 ton trucks.
2 of them look like they have free floating axles, these will take a much larger load for weight and towing. They are also heavier. Hub is held in by a large nut, simular to the front wheel bearings on a car. Axle is bolted to the hub.
The other one is from a light 3/4 ton and will weigh the least. For a spunky 302 , it should handle the abuse just fine. Keep in mind if a axle breaks, the wheel will come out of rear.
