1954Chevy5window, I did that job on my '36 Chevy pickup using information from this forum. The forum article explained that the Patricks 3.55 gears are the expensive way to do the job. The inexpensive way is to use a chevy car rear axle assembly with 3.55 gears from a '50-'54 powerglide equipped car.
The details are in the article and it sure worked for me. The only complicating factor on my '36 was the 3.55 hypoid gears wouldn't fit in the '36 spiral bevel housing so I adapted in a '37 Chevy car rear axle, shortening the torque tube and driveshaft and moving the spring perches inboard.
The replacement rear axle can be prepared while you keep your driver onn the road.
