With enough money, a machine shop could probably fit a 3.55 R&P in an HO52/72 differential. But you'd need to give them money by the truckload if you could even find someone to attempt it. The pinion on a 1/2 ton axle is overhung, with both bearings forward of the gear, while the HO52/72 pinion is what's called straddle mounted with bearings both forward and aft of the gear. Take a look at the attached pic clipped from the 1948-1951 Truck Shop Manual and you'll see that they're significantly different.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
