If you get as far as an entire rear axle swap...
The GM 14 bolt rear axle in my opinion is a better swap for the AD 3/4 and 1 tons than a Dana axle.
One common configuration of the 14 bolt is exact same width as the original axle.

Much to read about this conversion in the 1 ton section.

•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
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-