harrybolt,
There is a
casting code at this location. post the code and people might be able to help you ID the year.
I think the major external difference between the 47-50 and 51-54 is the "backing plate" for the brakes. There are two wheel cylinders on the earlier years (Huck Brakes), compared to the one top-mounted wheel cylinder on the later years (Bendix Brakes).
If you are changing the ring & pinion gears, the ring-gear carrier in the 54 rear end will not work with Patrick's 3.55 R&P set (you need an earlier carrier but it will then work in a 54).
