What is the deal? SBP 10"×1 3/4" backing plates.

[cop car wagon]

I was going to post these beautiful 10" small bolt backing plates, complete with all hardware, and park brake cables.
They are off a 71 or 2 dart 7 1/4, so the 5th hole would have to be drilled, but....
The 4 holes don't line up with an 8 3/4 axle retainer.
What am I missing? I thought all backing plates cross fit, and they only had offset issues for brake width.
I've run 7 1/4 big bolt 10x2.5 backing plates on an 8 3/4. How is a small bolt rear different?

 

[cudamark]

Nope, they've always been different and didn't interchange. The only other backing plates for the 8 3/4 with 10 X 1 3/4" brakes is the mid-60's B-body 6 cyl cars with a 7 1/4. They used the same brakes (except for the drums) as the A-body 8 3/4.

 

[cop car wagon]

So the drilling the 5th hole is just bs by those not knowing?
The top 2 holes look off too, which would make the drum not centered.
Looks like I have some really nice park brake cables and 10" spreader bars, e-brake levers then.

 

[RustyRatRod]

So the drilling the 5th hole is just bs by those not knowing?
The top 2 holes look off too, which would make the drum not centered.
Looks like I have some really nice park brake cables and 10" spreader bars, e-brake levers then.

View attachment 1716520551

View attachment 1716520552

Correct. Total and complete incorrect internet garbage nonsense. They are totally different from the 8 1/4, 8 3/4 and Dana patterns.

 

[JDMopar]

Correct. Total and complete incorrect internet garbage nonsense. They are totally different from the 8 1/4, 8 3/4 and Dana patterns.

How about a truck 9 1/4 thrown into that mix? Say, taking the brakes, backing plates and all and drilling the 5th hole to mount them on 8 3/4?

 

[RustyRatRod]

How about a truck 9 1/4 thrown into that mix? Say, taking the brakes, backing plates and all and drilling the 5th hole to mount them on 8 3/4?

I am not familiar with the details on the 9 1/4, other than it's a good rear end. If I had one under something, it'd stay there.

 

[cudamark]

The problem you run into is the offset for the A-body 8 3/4 with stock axles.

 

[RustyRatRod]

The problem you run into is the offset for the A-body 8 3/4 with stock axles.

That's exactly why, when messin with this stuff, I cannot recommend Cass at Dr Diff more strongly. He will tell you exactly what you need to go with what. He is the reason I have a completed Ford 9" rear end on the floor ready to go in Vixen. Chrysler 8 3/4 housing ends, small bolt pattern 10 X 1 3/4 brakes. It came out real nice.

 

[rbkt65]

The 9 1/4 plates can be used also. Most of my 11 x 2 1/2 brake kit backing plates come from trucks with 9 1/4. Dr Diff said that he can also make axles for the 9 1/4. Very pricey, but can be done.

 

[Dana67Dart]

Not to mention the center home is sized for 7-1/4 bearing OD which is smaller than the 8-3/4