I did search and still dont know how to id this without pulling it apart to count the splines on the axles. I was told its an olds but could be a pontiac? Here are the pics.
I think the brakes are about the same but there is some differences in the axle seals,the 53 olds I had years ago had some wierd axle seals compared to the rest.
Just go to FabCraftMetalWorks.Com for parts. Olds/Pont are the "same". 57 and 58 used 29 spline axles, 59-64 used 31 spline. There is also a thread in the Tech section here on the Olds/Pont rears. 57 Pont used used leaf springs, and you may be able to id your rear if it has stock, or remnants of, leaf spring pads; 58-64 Pont used coil springs and the brackets, or remnants, may be there. ALL Olds were leafs through at least 59; someone else may be able to say how the 60-64 Olds rears were sprung. My 57 Olds housing is 54" flange-to-flange (no axles, drums, or backing plates); 57 Pont is 54", but they take the same length axles. There are some minor differences in bearings, but they do interswap. The 31 spline rears use a wider housing and therefor axles, axles are 1" longer. Also, axles are the same length side-to-side, not one shorter/longer than the other. Axles from a 31 spine can be cut 1" and used in 29 spline housings (as long as a 31 spline carrier is also used). Some Ford 9' axle bearings can also be used; the early Olds/Pont bearing are pretty expensive. That's about all I can remember, off the top of my head, this early in the day. Butch/56sedandelivery.