7 1/4 to 8 3/4 swap question about brakes

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turbodart68

turbodart68

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See I have this 71 Dart and its getting a 440 whether it likes it or not. I also have this 8 3/4 that I plan to put in with it. My question is. Can I use the backing plates and drums from the 7 1/4 on the 8 3/4. Both rears are SBP.
 
I've seen this subject matter before...I think they are interchangeable, but lemme look around.
 
answer....No sorry. the 7 1/4 and the A body 8 1/4 & * 3/4 have a totally different backing plate.
 
They are different. Where are you located? I'm in Chino and I have a complete set of backing plates and drums. Let me know if you are interested. I do make a trip to Torrance every couple of weeks. They are
4 1/2" bolt pattern.
 
Are you guys sure about this? Maybe it changed in 73 but my 73 7.25 BBP seems to have the identical brake setup as my 73 8.25 BBP although I swapped everything EXCEPT the backing plates. They sure look like they would swap as well.
 
I switched my 8 3/4 to big bolt pattern and used the brakes and backing plates from the 7 1/4 that was under my 74 dart and every thing bolted right in place.
 
Here's a couple pictures of my 8 3/4 with the 7 1/4 stuff on it. But then again this is bbp not sbp.
 

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I'm not positive, but I think "it depends". Most, if not all SBP 7 1/4 brakes were 9 inch. These will not fit the 8 1/4 or 8 3/4. If the 7 1/4 brakes are 10 inch BBP, I'm pretty sure they will fit, if you use everything. Look at the number of mounting holes in the 10 inch 7 1/4 backing plate. If it has 5 holes, I think it will fit. If it has 4 holes, it will not fit.
 
Backing plates from a 5 x 4" bolt pattern 7.25" rearend will not bolt to an 8.75" rearend.
 
The doctor is in! So there you have it the BBP ones will swap but the SBP ones will not. I just looked my BBP 7.25 has 5 mounting bolts, and 10" drums.
 
I swapped a 8.75 to replace my 7.25 in my 75 Scamp. Since the 7.25 was big bolt pattern, the backing plates for the 10" drums bolted directly onto the 8.75 housing.
The difference I believe is when you have the small bolt pattern.
 
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