I've swapped to 8R19.5 tires and suitable wheels.
And 4.10 axle gears.

Otherwise just been driving, it's happy at 50-55 but can handle the interstate for a stretch here and there at a brisker pace, and once had it over 70mph briefly under its own power.

•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-