I believe you'e responding to a 10 year old thread.

We now have a tech tip on swapping gears for the 3/4 and 1 ton trucks.
https://www.stovebolt.com/techtips/axles/1%20Ton%20Upgrade/

1/2 ton will have (originally had) 6 lug axles and an enclosed driveshaft.
3/4 ton has 8 lugs and open driveshaft, at least at the differential.

•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-