The lack of gear options would have me looking at a 14 bolt axle instead.
What ratio is it?
I'm also guessing the Rockwell has 10 lug wheels and 8 might be easier for a 1 ton.

What's the overall plan/goal.

•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-