I also have a 52M38 with 11" brakes. I used google images and rock auto to figure out what they were off. Turns out they are off a 68 ford F100 or similar.
Good luck
Post a photo of the shoes.
Thanks Wes,
Rules reviewed.
I've been reviewing manuals but am struggling to ID my backing plates still.
I expect to have the M38 driving again today. Fingers crossed.