I'd expect king pin differences and from there small differences in everything.

Easy enough when comparing axles to either measure and or look up the king pin diameter.
Chances are if they're the same diameter some if not all parts will interchange.
Similarly if the kingpin diameters are different don't count on anything to swap but might get lucky and find something does.

•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-