Not worth the trouble on these trucks but one answer is new much longer spring packs.

I added firestone air helper springs over the axle between the frame on my 48 2 ton. Used stock firestone brackets for the axle side and made the uppers. Springs I'm using are new and made for my one ton, actually had them made stouter than stock for that. I put about 8,000 miles on them on the 1 ton and it rode very nicely, did a cross country trip and then some.

So not sure I see the point in doing anything... they're not bad to start with, just drive it.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-