71 rear brakes

[RodnRudy]

I bought a 71 rear end to put in my 68 for the 5 lug pattern and after deciding to put new seals and bearings in it I found someone had tack welded the center pin and bolt to the carrier. I removed the welds expecting the pin bolt to be broken but every thing came apart okay. Pics show before and after cleaning up the welds.
New bearings and seals are installed. I also found that the ring and pinion has been changed from a 3.73 to a 3.07. That's fine because I'm running a 350 turbo. Lucked out there.
Next, in looking at the backing plates I find that there are two adjuster wheel slots in them, one at 4:00 and one at 8:00. I don't think the backing plates are for the 11" x 2" brakes but the brake shoes and hardware fit fine. Any body know what these backing plates can be off of? Thinking seriously about cleaning up the backing plates from the 68 rear and using them. This seemingly simple upgrade has turned in to a challenge but I'm not giving up!