anybody have comparison pics between 8 1/4 and 8 3/4 drum backing plates??

That would be great. I would like to see for myself. I have heard they are different and others say they are the same. I need to figure out why my 73 duster drums are hitting my 72 8 3/4 plates.

Are you running big bolt pattern in the rear now? If you are, you can't use the 72 small bolt backing plates, this will cause the brake drum to not fit, you will need backing plates from a big bolt pattern rear.