They're 10" wide wheels.....
Stock or compariable 17, 18, or 19.5" rims are about 5-6" wide.

If you don't want stock 17" why not some common 16"? I ran 16" snow tires on the back of my 52 1 ton in the winter, think they came from a later Chevy or ford, they were free and fit so I wasn't picky.
Point is there are used (cheap) wheel options if you look around and aren't afraid to try some on. 19.5" are a good choice but if you can't turn any up look for something else in the meantime.

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-