OK things are a lot clearer now.
One other caveat, I've located a set of backing plates that are 11 inch. But here's the other sadly and uniquely Canadian thing. I found out this summer when swapping an 8 3/4 out of a 68 Dodge (unknown model) that it came with 11 x 2 inch shoes. Let me tell you they are ridiculously difficult to find.
So one more question is there a way to check that these backing plates I found are not for the 11 x 2 inch shoes?
Edit.
PS the 68 Dodge 8 3/4 went into my son's 56 Custom Royal
