GM pattern rear drum backing plate for 3.150 bearing
 

Are there any backing plates available for the 3.150 diameter bearing -or just get out the die grinder?

I’m curious on this too .

I could not find one so cut a template and marked the backing plates with a die grinder. NOt a lot of meat adjacent to the holes. I fact the T bolt adjacent to the shock bracket on a '65-67 A Body 12 bolt would not allow the T bolt to go in so I had to grind down a nut and use a bolt!

I rigged this up with some inexpensive hole saw bits off of Amazon. The red one is 70mm the same size as the GM hole and is used just to center and guide the black one that is 80mm . I matched up a metric bolt at ace . Worked great, I used 2 scrap pieces of 4x4 to lay the backing plate on and knelt down to brace it . Only hit myself in the nuts with the drill twice - worked great !

Good engineering!

That's a great idea. I have a Moser 9" coming for my 1976 Firebird and I am going to use the 11" rear drums set up that I swapped on the stock 10 bolt a few years back.

I can tell you the 3.150 ends on a 65 12 bolt A body rear have two of the T bolts you can not slide in! And even grinding a nut to slide back there NS to use a bolt on the outside it is awful thin using the GM pattern! Probably going to use the Ford pattern on the 9" for the Impala project.

Everything went together fine on my QP 9 and stock modified 68 backing plates ant QP t bolts .

I'm not sure if since the 65-67 are a hair shorter the ends are closer to the shock bracket and why I could not snake one in even grinding the head on the T bolt some.