8 3/4 Big bolt Conversion axles. What Backing Plates?

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DUSTY_76

DUSTY_76

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Hey, I am converting my 76 Duster's rear end to an 8 3/4 from the original 8 1/4. All I have for the 8 3/4 is the housing, and plan on getting the large bolt pattern conversion axles for it. I have read and been told to get B or E body backing plates and brakes for it. The question I have is, will the backing plates and brakes from my 8 1/4 work/fit? or No? They are 10". I would like to be able to use them so I do not have to find and buy another set. Any help would be great. Thanks.
 
Use what you have for some reason 11" drums are about 3 times the price at the parts store.
 
Ok. Thanks for the reply's. I was concerned that the 8 1/4 backing plates would have some sort of different offset or something compared to backing plates from an 8 3/4. But if this isn't the case. Perfect! Thanks again.
 
DUSTY_76 said:
Ok. Thanks for the reply's. I was concerned that the 8 1/4 backing plates would have some sort of different offset or something compared to backing plates from an 8 3/4. But if this isn't the case. Perfect! Thanks again.
Click to expand...

Nope. All the BBP brakes are set up for the same axle offset- 10x2.5", 11x2", 11x2.5" and 11x3" BBP rear brakes all use the same axle offset. The backing plates can be swapped between BBP 7 1/4's, 8 1/4's, 8 3/4's, and even Dana 60's.

The backing plates do have to be matched to the shoes/drums, ie, you can't use 11x2" backing plates with 11x2.5" drums and shoes because the backing plate offset is different to make up for the axle offset being the same. But on an 8 1/4 I'm guessing you've got the regular 10x2.5" stuff that's everywhere.

Be sure that you specify you'll be using standard BBP brakes when you buy the axles. There are axles out there that are intended to be used with re-drilled SBP brakes, and you don't want those if you're going to use BBP brakes. Call Cass, aka Dr. Diff, and tell him what you'll be using and he'll get you all set up.
 
This might help some.
 

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All 8 3/4 chunks interchange. Count the splines in the side gears before ordering axles.
 
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