Was there such thing as a 9-1/4 or 9-3/4 in an a body? There is a 75 Duster at a yard here with a rear end that has 10 bolts on the back, but seems to be bigger then an 8-3/4" rear, deffinately bigger then a 7-1/4. I believe the car has a 318 in it, with 727 auto tranny. Any easy way to distinguish the 9+ inch rears?

Also assuming it isn't a stock option, were there any other bigger rears off of trucks that were bolt on to the A bodies?

Yes, the 9 1/4 was the optional HD rearend in the 73 and up V8 cars.
These are really big units so they are somewhat heavy.
I will have to look to see if these use axle holding "C" clips.
DD

If it has 10 bolts and the cover is basically round it is an 8 1/4. The 9 1/4 rear end has 12 bolts and the cover is octagonal. The Dana 60 (or 9 3/4) has a 10 bolt cover but the sides are flat and the rounded top/bottom are off set to the drivers side.

The 8 1/4 rear end has a bigger center section casting than an 8 3/4 and it was the heavy duty replacement for the 8 3/4 in A-bodies starting in 73.

I do not believe that a 9 1/4 was ever offered in an A body from the factory. The Dana 60 was only offered in the 68 Super Stock Hemi cars with 4 speeds.

The 8 1/4 uses axle holding C-clips.

The car you describe would also be a likely candidate for a disc brake swap.

_________________

Dave Clement
68 Barracuda (Hot-Rod \6)
http://mysite.verizon.net/vze4pgxf/

9 1/4" was the cheap replacement for the 8 3/4" in all the other models, I've seen it under a lot of New Yorkers and Cordoba's from the mid-70's. The late A-body got the 7 1/4" standard with the slant, and with some 318 2-V packages (usually an Auto and 2.76 geaing for mileage...). The 8 1/4" became the HD/Performance rear behind disk brake packaged slants,tow package cars, 73' 340 and 74-76 Duster 360's...My 1974 car came with 225,3spd manual, disk brakes and a 3.21 8 1/4" under it..nice package.

Oddly I've seen a lot of 1973/1974 400 big block Fury and Newports with the 8 1/4" rear-end...so it must be ok for a no-performance big block.

8 1/4" and the 9 1/4" are both C-clipped axle type rear-ends so don't do any 24-7 bullitt runs.

-D.Idiot

an A-body 8 1/4" rear...under my Feather Duster:

I have determined the rear I was looking at is indeed an 8 1/4"

The car already has 4 wheel disc. Got the front disc, but left the rear because I will be getting a 8 3/4" rear end from a parts car I have. I didn't think that they would be interchangeable. Someone correct me if I'm wrong, then I could go back and get the rear disc stuff too.

The only issue I might have is this.. from my understanding, the 8 3/4" rears from 72 and earlier had big bolt pattern (parts car is a 72) so therefore the rear I'm getting has big bolt pattern axles. The front disc setup I just got on the 75 car (73 and later have small bolt pattern?) is small bolt pattern. So either I have to get small bolt axles for the rear, or hold out and keep looking for a big bolt pattern disc brake setup (I want all the wheels to be same pattern so I can rotate tires and not have to carry 2 spares)

It would be beautiful if the small bolt pattern axles from the '75 8 1/4" would fit in the 8 3/4" from the 72 donor car, but they are way different, right?

Also a question about the rear end swaps while I am at it... I know it has been said that all you need is to shorten the driveshaft, but no one mentioned anything about the yokes. Isn't the yoke on an 8 3/4" bigger, therefore needing different u-joints, therefore different drive shaft? Or do I have to change the yoke on the 8 3/4" to match my drive shaft?

Pierre,
All A-Body 8 3/4 rear ends have the small bolt circle. All 8 1/4 A-body rear ends have the big bolt circle.

If you got the disk brake set up from a 73 or newer it will be big bolt pattern. The only small bolt circle stuff after 72 was the 9" drum brake cars.

_________________

Dave Clement
68 Barracuda (Hot-Rod \6)
http://mysite.verizon.net/vze4pgxf/

I call the 9 1/4's 'midi-Danas', because the center sections look much like a Dana 60. All the ones I have seen, have tapered axle tubes. Yes, they are very heavy. I've seen them in lots of B & C bodies and 1/2 ton P-ups. I don't think that much of them, I swap them out for earlier B-body wagon 8 3/4" axles ass'ys.

_________________
'66 Cuda 225/4spd
'66 Dart GT convertible 225/auto
'64 Dart GT 340/4spd

Did I hear you say the junkyard car has REAR discs on it? If so, grab them IMMEDIATELY! They are some sort of aftermarket conversion. That setup is definitely worth something, as they never offered a rear disc brake setup from the factory for A-bodies.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

YES GRAB THOSE REAR DISCS!!! those will be worth some large coin! and they are pretty rare to boot!

Justin

the late model imperial (that last ones to be Battleship sized.... had the option of 8 1/4" rear disc brakes... so they might not be a newer style conversion so much as, maybe an older knock together patch-it..

-D.Idiot