I doubt the problem is the rear shocks. An easy test would be to remove them from the truck and drive it. It would not surprise me if removing the rear shocks would be noticed much at all. I had one come of at the bottom and just hung there for who knows how long, but did not notice any difference in the ride.

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission