OPs Backing Plate
How many adjuster slots?
View attachment 1716231941
65 to 70 Mustang 10X1.75 rear backing plates (I believe ford 9" "small" looks like from the Ebay listing they are KH manufactured)
(Note that there is only one adjuster slot)
Also note the difference in the stamping and the bolt spacing and center hole compared to A body 7 1/4 and 8 3/4 10x1.75 backing plates
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68 and older Chrysler A Body 10x1.75 8-3/4 backing plate
(Note that there are two adjuster slots)
View attachment 1716231944
69-72 7 1/4 10x1.75 backing plate
(Note that there are two adjuster slots)
View attachment 1716231951
Axle Flange Housing Identification
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Here are some photos of my 67 7 1/4 10x1.75 brakes Small bolt pattern
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