Brake shoe size

I hope I am not high-jacking this thread, but I pulled a drum off of the back of my 64 dart, 8 3/4 10" x ?, because it locks up when I step on the brakes, and noticed that there is a good 1/4 inch of more of unused drum on one side of the shoe. The shoe measures less than 2", so I am assuming someone, not me, put the wrong shoes on it. The question is do I need 2 1/4 or 2 1/2 shoes ? or do I need to measure the drum better? I know I need a different proportioning valve, that is a different subject.


Thanks


PS. dual master, front disks from a 69 and all small pattern.
Above discussions cover front drums.
If the 8.75 came complete from a '69 A-body, the rear drums are nominally 10 x 1.75". Shoe frames should be stamped 331 and the adjuster hardware should be the '69 up type.