The 2” spindle nut, if it is, is what the 14 bolt uses, as already noted.
In addition to the previously provided part numbers some alternate numbers at possibly better prices can be found here.
https://www.stovebolt.com/ubbthread...-14-bolt-axle-swap-info.html#Post1249919

•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-