11" backing plate question

so i am going to pick up an 11" drum set from a 76 cj7 tomorrow a.m....i know the rear is the model 20 and the backing plate holes are different,,but the question is, can they be drilled out to work,,i checked the parts through napa and the drums/shoes are the same,,,have any of you guys visually seen them side by side to know if they can be drilled out..a disk brake kit for a model 20 showed 4 holes in a backing plate...was wondering about adding the others...

 

I think the offset as well as the bolt pattern is gonna get you.
The 20 plates have a deep dish to them
whereas the backing plates you want/need are flat with very little dish to them
look at the fronts tomorrow, you'll see the difference.

 

ok,,either way i'll have a spare set of stuff to play with(drums/hardware)

 

Jpflat2a is right. The AMC 20 rear backing plates won't work due to offset differences, hole sizes, etc. The hardware and drums will but not the backing plates.

 

thanks guys..i got the 11" fronts and rears along with the factory rollbar for $100....now all i need is 2 more backing plates