8 3/4 rear sbp to bbp help needed plz

-
D

DemonGuy340

DnP
Joined
May 26, 2014
Messages
181
Reaction score
1
Location
Atlanta, Tx
Hey I got a question. Is there a way to make a 8 3/4 rear from a 71 duster swap from small bolt pattern to big bolt pattern? I kno theres probly adapters but dont know if its a good idea or if theres a better way. Thanks alot for any help.
 
There are 2 basic ways to do it:
1) take original axles and drums to a machine shop and have them re-drilled to desired bolt pattern. Studs end up near outer edge of axle flange but works well for moderate HP applications and maintains stock rear brakes/hardware.
2) Buy aftermarket axles or have C-body or truck axles cut and resplined to proper length then convert to B, E, or C body backing plates brakes adn drums. Note this option widens the track by 1/2 on each side of that matters to you.
 
Original A-body axles must be PLUG WELDED and re-faced in addition to being re-drilled.

5 x 4.5" bolt pattern A-body axles set up for standard B/C/E body brakes increase the track-width 1/4" per side.

This is usually a non issue, as common 15" Mopar spec wheels work nicely with the combination (15 x 7" with 4.25 BS, 15 x 8 with 4.5" BS).

BTW, a new 5 x 4.5" A-body axle pkg runs $295 pair, assembled:

http://www.doctordiff.com/axle-package-stock-length-mopar-5x4-1-2-bolt-pattern.html
 
Re-drilling the stock sbp axles means re-drilling the stock sbp drums and keeping the sbp brakes. Which is fine, but stock sbp drums are getting harder to harder to find.

New axles will get you the BBP, but most also use the 10x2.5" BBP brakes, which is a real plus in my opinion. Parts for those brakes are much easier to find. Keep in mind you need the 10x2.5" BBP backing plates for that brake swap because the offset is different for those backing plates than the offset on the sbp backing plates.
 
Buy new bbp axles from Dr Diff and find some bbp drum brakes or get a disc brake kit from him.
 
Get new axles and see TSM for disc brakes..... just because it's a 1970 body doesn't mean the rest of it has to be 1970..

upgrade
 
Supershafts said:
Get new axles and see TSM for disc brakes..... just because it's a 1970 body doesn't mean the rest of it has to be 1970..

upgrade
Click to expand...

Doctor Diff also has great brake packages that use the factory tapered bearings...
 

Attachments

  • 8.75 done almost.jpg
    62.4 KB · Views: 163
Whether from Cass or not ( Dr. Diff ) , new axles are the clear way to go.
But I'll go on record as saying he is one of the best in the business for MoPar stuff.
My last deal through him was for a drive shaft from Strange , but I had a MW yoke I planned on using.
No problem.....he provided me with the RMA to send my yoke to Strange so they could balance the shaft and yoke together.
Better yet , he called me at home to suggest this.
THAT is the kind of customer service that Daddy likes !
 
You must log in or register to reply here.
-

Back
Top