Seems a frequently asked question is "how get better gears so I can cruise at current hiway speeds?".
I bought this Chevy motor home rear axle 11,000 lb axle
a few years ago to put under my '38 1-1/2 ton.
Axle ratings for 1-1/2 ton trucks up through '54 are also 11,000 lbs and the width is identical to my '38. The bolt pattern accepts '54 big truck wheels or later model 19.5's.
The motor home axle is a Dana 80 with parts and a wide range of gear ratios readily available.