I think it could hold up, as I hinted at earlier it depends on the use.
A 41 1.5 ton is not that big a truck and the stock 6 cylinder is not all that strong.

If the truck is never loaded and just goes to shows and parades then the T-5 probably has a chance.

If used as a truck then it may not last, or you'd have to be careful how you drive, but you can buy several more T-5 transmissions for what they want for a gear vendors...

How will the truck be used?

Grigg

•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-