10" rear backing plates??

These are Pic;s of backing plates and 10'' drums on newly installed 8 3/4 rear end. Drum is from 7 1/4 that was taken out.
Can't figure out what shoes will fit, or if backing plate, drums are wrong?
I was hoping to get this done before cold weather, but garage is damp and cold now. Ohhh well it'll warm up in 6 months.
Thanks for having a look!