anybody have comparison pics between 8 1/4 and 8 3/4 drum backing plates??

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evil 340

evil 340

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I would like to see a pic of an 8 1/4 and 8 3/4 drum backing plate. To see if they are different. I know one of the technical guys on here will have what i m looking for. This is the most helpful site i ve ever been on. Thanks in advance.
 
yea they are the same. some of the new 8.25 rears only have 4 bolts but you can just drill the 5th hole.
 
The 8 1/4 will have a flat spot where the fifth goes instead of being around if I remeber correctly. I want to say the flat spot was on the top. I
Can take some pictures in the morning though.
 
That would be great. I would like to see for myself. I have heard they are different and others say they are the same. I need to figure out why my 73 duster drums are hitting my 72 8 3/4 plates.
 
backing plates are the same? what accounts for the difference in the drum widths? 8 .75 a body are set -up for 1.75" brakes, the 8.25 are set up for 2.25"

can't be the same? Lawrence
 
evil 340 said:
That would be great. I would like to see for myself. I have heard they are different and others say they are the same. I need to figure out why my 73 duster drums are hitting my 72 8 3/4 plates.
Click to expand...

Are you running big bolt pattern in the rear now? If you are, you can't use the 72 small bolt backing plates, this will cause the brake drum to not fit, you will need backing plates from a big bolt pattern rear.
 
when i said they are the same i ment they will bolt up as a set and fit...

unless your running 8.75 brakes of a b,c, or one of the boats then what you have are small bolt pattern 8.75 stuff, those only have a 2" offset. same as small bolt and some large bolt 7.25's.

Now all you big bolt 8.25's, 8.75's, D60, 9.25 with 5x4.5 pattern all use the standard 2.5" offset, and the brakes will swap AS A SET between those axles.
 
BBP 8 3/4 and BBP 8 1/4 backing plates are the same. As kid mentioned, all of the BBP backing plates are the same and can be used on any rear end, from 7 1/4 all the way up to the Dana.

But small bolt pattern A body 8 3/4 backing plates are different from EVERYTHING, and only work with SBP A body 8 3/4 axles. If you want to run 10x2.5" BBP drums, you have to get BBP axles and backing plates.
 
So i need bbp 8 1/4? Since i already have 73 duster drums.??
 
I have a 72 demon 8 3/4 with Yukon axles bbp 5 on 4 1/2. 73 duster drums and the drums are hitting the backing plates.
 
Was the axle offset set-up for stock A body axles?
Which backing plates are you using?

As said above, the stock A body 8.75 backing plates will only work with stock A body offset axles. The brake backing plates for the A body 8.75 are unique.

Any large bolt pattern 1965 and up rear brakes will fit when swapped as a complete set-up. 7.25, 8.25, 8.75, dana.
 
Yeah. I kinda mixed and matched. Stock 72 8 3/4 plate and the drums are 73 duster. Hardware as well.
 
Thanks everyone so far. I haven t fixed the prob yet. I did buy a set of skatez for the whole car to roll around my shop tho. Lol.
 
More like mixed and mis-matched :D

have you got the backing plates that went with the 73 drums? There's your solution...
 
No. I bought new drums and guts. They don t have the plates tho.
 
Thanks coffee but i ve got 4 sets on the line now. Those might work tho. Thanks again.
 
I used 8 3/4 plates on my 8 1/4 and 1 hole isn't used on an 8 1/4
 
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