DUSTER DEMON 4in Bolt pattern drum sizes
many parts stores have idiots behind the counter. You probably have 10 in. My rear was from 70 duster. I got mine from RockAuto.com Do a part number search for BD60123 made by Wagner. They were $50 ea. Here's a couple pics. They fit perfect on my A-body 8 3/4. Try this link.
http://www.forabodiesonly.com/mopar...ighlight=wagner
Sorry bad link to another thread on FABO