I recently acquired a NOS pair of Kelsey Hayes brake drums as part of a larger local parts buy. The numbers cast into the drums include KH125944 and 97455. The machined surface measures 10x2" which leads me to believe that they are for 10x1.75 shoes. Here's the kicker, they aren't 5x4" as you would expect, but instead 5x4.5" with the correct BBP register.
Any idea what the application is? Hopefully the pics below are helpful