Is there anyway to have rear shocks installed on these trucks!
Leaf springs actually have some dampening effect. The leaves slide against each other, resisting movement in both directions like a shock absorber.
Your spine probably doesn't believe me.
Sure, you can put shocks on it. I can't recall offhand how international does it from the factory, but one method is to put a shock mounting plate at the bottom of the spring stack. This means loosening the long u- bolts. Honestly its easier to torch them off and install new ones. You will need a couple of giant jack stands, an air jack, a torch set, and an impressive torque wrench to do this successfully.
You'll then need a pair of upper shock mounts and shocks of the correct length. Hopefully holes already exist for the shock mounts. If not, you'll want to get your hands on a mag drill.
The shocks will let you know if the length is wrong by snapping the rod. It's a feature!
How about an air-ride seat instead?
Many trucks of this size come with no shocks in the rear. Their purpose was strictly utilitarian.