While trying to find new rear drums for 11" brakes from an 8-3/4 rear end, I can't find any with matching dimensions. The outer diameter is 12-5/8", and I can find one with that diameter, but the height of the old drum is 3-1/2" and everything in Rock Auto's catalog is at least 4".

I'm not sure what the rear end came out of, but the width suggests it's from an E-body, yet nothing in the E-body section of the catalog matches. I'm guessing a previous owner changed something.

Any experts on the various 11" brake combinations? Are there different 11" backing plates?

Found it...drums are no longer available.

A NAPA source said they could get them but their cost was over $100 each. I ordered used backing plates and guts, and drums are less than $50.

The ones I have were used on some E&B bodies and some trucks.