Are you looking for single wheels or duals? You said single wheel truck, but sounds like you’re test fitting dual wheels?

I’m pretty sure you’ll need 19.5” duals to fit over rear drums, and even then might just fit.
Single wheels 16” ought to fit, but probably not all.

•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-