SBP 10" rear brake drums and shoes
You're gonna have fun finding those in an ordinary parts store, and I'm not sure that even Rock Auto carries the rear drums for an A body 8 3/4. 70Duster is correct, they are 10x1 3/4" and that is the ONLY size an actual A-body 8 3/4 has, unless it has been changed or reconfigured.
Now, if you want to find these drums and related hardware, give Craig Studnick a call at 516-485-1935. He knows Mopar brakes like the back of his hand and carries most all of the hard to find stuff. He's quite a character, so gear up when you talk to him, but he'll set you up!! Good luck, Geof