7.25 Brake Backing Plate Interchange

I've got a 7.25 rear end with 9 inch drums I would like find some 1O inch backing plates. My understanding is only the 7.25 has 4 mounting holes, all others have 5. Meaning that the only source is from a 7.25 with 10 inch brakes.
Am I correct so far?
I know that the ten inch brakes appeared on 7.25 rears in 1965. The 7.25 has never gone out of production as far as I know. I'm thinking of the Dakota and some Jeeps. Did they retain the 4 bolt mount?
What vehicles can provide a 10 inch backing plate with the 4 bolt mount usable on my early 7.25?

The number of bolts for the backing plate isn’t really that big of an issue. The backing plate offset is though. If you’ve got the 5x4” small bolt pattern axles then you have to use 10” backing plates from a small bolt pattern 7.25 rear axle. That’s about it. So your only donors are A-body’s with a small bolt pattern 7.25” and 10” brakes. The later large bolt pattern 7.25” stuff does not interchange with the small bolt pattern 7.25’s.

Sent a PM - I'm gonna make your day!

I was wondering about this in a different way - I’ve got a set of 65 7.25 10 in backing plates complete with new brakes and e brake cable that I was wondering if the 5th hole was drilled, could they then be used in a SBP 8.75?

Ogre Backwash said:

I know that the ten inch brakes appeared on 7.25 rears in 1965. The 7.25 has never gone out of production as far as I know. I'm thinking of the Dakota and some Jeeps. Did they retain the 4 bolt mount?
What vehicles can provide a 10 inch backing plate with the 4 bolt mount usable on my early 7.25?

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I think you are confusing 7-1/4 and 8-1/4. It was variations of the 8-1/4 that are/were used in
Jeeps and Daks. A 7-1/4 just wouldn't make sense in a truck or a Jeep.

When I converted my 1964 7-1/4 to 10" brakes a couple years ago, i just sourced the CORRECT backing pkates on FABO. Why make things more difficult?

str12-340 said:

Sent a PM - I'm gonna make your day!

Click to expand...

Mike, you made my whole week! Thank you again.

65 Dartman said:

I was wondering about this in a different way - I’ve got a set of 65 7.25 10 in backing plates complete with new brakes and e brake cable that I was wondering if the 5th hole was drilled, could they then be used in a SBP 8.75?

Click to expand...

I doubt it. The 7.25 uses a 2.5" axle tube. The 8.75 uses a 3" tube. However, in 1982 They increased the tube size to 3" when they changed from tapered bearings to roller bearings with c-clips. The center section is the same and the tubes neck down to 2.5" to fit. Actually those probably wouldn't work either. You still have flange thickness difference to deal with. These later brakes are probably the same as the 8.25" brakes.

I think you are confusing 7-1/4 and 8-1/4. It was variations of the 8-1/4 that are/were used in
Jeeps and Daks. A 7-1/4 just wouldn't make sense in a truck or a Jeep.
When I converted my 1964 7-1/4 to 10" brakes a couple years ago, i just sourced the CORRECT backing pkates on FABO. Why make things more difficult?[/QUOTE]

Why NOT make things more complicated? That's what we get for liking MoPar. If we wanted simple, easy and cheap we would all be driving Chevys.
Anyway it looks like I've been saved from my dilemma through the generosity and non-profit, philanthropic spirit of FABO. Thank you, you know who you are.

In regards to 7.25 usage, according to my sources,("Differentials" by Jim Allen and Randy Lyman):
7.25 rear-
63-89 Chrysler, Dodge, Plymouth, mostly 6 cylinder.
87-98 4x2 Dodge Dakota 4 cylinders and some V-6

7.25 Front- (IFS)
87-96 front of Dakota 4x4s

No listing for Jeep. I may have been thinking that because the 7.25 is a Spicer-type axle that there was actually an equivalent Dana/Spicer model number such as Dana-Spicer 27, 30, 44 or other such trash. I was surprised that there wasn't. So it seems that we are both right after all.