So, here are the questions again, and the answers as I interpret them so far.

1. What years were they used?
1960-late 80's

2. What size trucks used them?
1.5 ton and later on both 1.5 and 2 ton.

3. What makes, Chevy for sure, GMC?, other brands?
Just GM

4. Was there any make/model/year that is more likely, or the most likely to have the 22.5" wheels?
No idea yet, other than guessing that later are more likely to have 22.5

Any additions or corrections?

Thanks,
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-