As already answered the cabs are interchangeable for all 1948-1953 GM trucks (except COE) from 1/2 ton to about 3 ton (400 series GMC). You can even swap late 47 and the 54 and early 55 models.

The difference that you are concerned about with the 48 model cab and the later one is the rear cab mount. The 48 has one center rear cab mount and this can be reused on the later frame, two holes may or may not need to be drilled in the frame crossmember.
Or you can adapt the later model twin rear cab mounts to the under side of the 48 cab. That involves buying and or salvaging and welding in two sheet metal reinforcing braces under the cab, not quite as easy.

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-