Yep, front tread width will be the biggest problem, and one without a good looking solution. I suppose you could raise the cab and fenders up so high that the wheels clear the fender lip, but they will still be outside the fenders.
Narrowing the front axle is not a good solution, because the frame would have to be narrowed too.

All that said, I am reasonably sure it could be done, but to me sounds like lots and lots of work, and/or an ugly truck in the end.

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-