rear brake shoe size

Those are very unique cars you men have -- or there was an upgrade that happened before you owned the car......

By the book -- and we know it is sometimes not 100.00% correct ---
slant sixes "Never" came with the 4 piston caliper disc brakes -- that was limited to a small fraction of the "top end" cars --- and all equipped with 8 cylinders....

And again, by the book, --- the 8 cylinders with 4 wheel drums had
10" x 2 1/4" on the front and 10" x 1 3/4" on the rear......

So if you have what you have and it is factory original -- it falls under the category
of the Chrysler world did some strange things --- that we know about --- and more that
we learn about through the years!!!!!!!!!!!!!!!!!!