I doubt they will fit the front.
They will fit the front of the next size larger GMC. They will rub the springs at a hard turn, you may be OK with that?, and they will possibly rub the fenders.
Should fit the rear, and make the truck faster.
You may have a little trouble actually getting them on the rims, because that size tire usually likes a slightly wider rim, but I would think they will fit with some elbow grease.

•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-