Duster rear end compatibility
- Thread starter builder89
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junkyardhero
Well-Known Member
no matter which axle, there will be modifications needed to make it bolt up.
The easiest swap is a 65-67 B body.
It will fit without mods*
71-74 is a lot wider and the perches are a LOT farther apart.
65-67 is only an inch or so wider than an A body axle and the perches are only 1.5" wider and will actually work as is.
It will fit without mods*
71-74 is a lot wider and the perches are a LOT farther apart.
65-67 is only an inch or so wider than an A body axle and the perches are only 1.5" wider and will actually work as is.
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MOPAROFFICIAL
Oogliboogli
Bolt up, yes.. 'this is a jk, a lot of things will bolt up with hammer n crowbar'
right size ? No. Too wide.
Some people here need a 'reset'.
One argument too many and they become an ultra sensitive and overly critical butthole.
Fwiw I've used 8" ford rears... they do bolt up..just figure out your brake hose,cable and u joint.
go get yourself a book called..
Chrysler performance upgrades
it lists these dimensions/fitment details
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The 65-67 B-Body rear can only be forced to bolt up and is wider. The perches are an inch farther apart. Take the time to find an A Body rear, 8 1/4 or 8 3/4 or send your housing off and have someone good shorten the housing and move the perches where they should be.
Unconventional
Well-Known Member
With the perches wider, it's gonna cut into your tire and wheel clearance too 
You’d have to move the perches for sure, on a 71-74 B they’re 47.3” center to center vs 43” for an A body.
That rear axle is also like 63” drum to drum, which IMO will be too much. I run a 68-70 B body rear in my Duster and it’s 60.125” drum to drum, and I’m already running quite a bit of backspace to make it work. And I run 18” wheels, you couldn’t get off the shelf 15’s even with what I run. The additional ~1.5” per side would make it very difficult to find wheels in any diameter that would fit.
3/4" per side is VERY easy to get to "drop on" RE: a 65-67 axle in a Duster.
VERY EASY.
Are there technical engineering concerns? Yes.
Does it work without modification? Yes.
Will you experience problems? I never did in the five plus years I ran one that way.
Also, the "extra" overall width actually puts the rear track exactly the same as the front track of factory disk brake cars.
...and 65-67 axles are about 1/3 to 1/5 the cost of an A body 8 3/4 and WAY (WAY) more plentiful.
VERY EASY.
Are there technical engineering concerns? Yes.
Does it work without modification? Yes.
Will you experience problems? I never did in the five plus years I ran one that way.
Also, the "extra" overall width actually puts the rear track exactly the same as the front track of factory disk brake cars.
...and 65-67 axles are about 1/3 to 1/5 the cost of an A body 8 3/4 and WAY (WAY) more plentiful.
The width of the axle isn’t the problem. I use a wider 68-70 B body 8 3/4 in my Duster. The problem is you’re cramming an axle with perches at 44” onto springs centered at 43”. A 1/2” of side load will absolutely compromise how those springs function.
Just because you didn’t die doesn’t mean it’s a good idea. Not noticing the difference is a reflection of your skills and abilities more than it’s a reflection of the actual performance. Those springs will not function correctly.
It’s only a “bolt on mod” if you’re a shade tree hack. Doing it right means moving the perches. It’s that simple.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Just so you know;
as for the 7.25, if that is what is currently in the Duster,
will not BLOW up with the first throttle application;
Not even with a hi-torque 340........
so long as you don't shock it with neutral-drops, nor peg-leg it, fresh oil could carry it for many years..
A limited slip will be a life-saver. However,
I would NOT run it behind a 360LA with a clutch, unless it was a dead-stock Lo-compression unit.
as for the 7.25, if that is what is currently in the Duster,
will not BLOW up with the first throttle application;
Not even with a hi-torque 340........
so long as you don't shock it with neutral-drops, nor peg-leg it, fresh oil could carry it for many years..
A limited slip will be a life-saver. However,
I would NOT run it behind a 360LA with a clutch, unless it was a dead-stock Lo-compression unit.
QUINN FORBES
Greendemon
My experience was…
7 1/4 lasted a year behind a healthy 318/727 but I abused it large, like I was trying to break it!
In a 70 duster.
Chewed up the axle gears (spider gears) then spit them out.
I swapped an 8 3/4 from a 68 B body and its still in there. No clearance issues with stock rims. 15”rallies.
I previously swapped to LB pattern.
Only mod I did was replaced perches 1/2 “ inboard each side.
72 B 8 3/4 was too wide even for a duster/demon for me.
No issues after that.
Good luck whichever way you decide.
7 1/4 lasted a year behind a healthy 318/727 but I abused it large, like I was trying to break it!
In a 70 duster.
Chewed up the axle gears (spider gears) then spit them out.
I swapped an 8 3/4 from a 68 B body and its still in there. No clearance issues with stock rims. 15”rallies.
I previously swapped to LB pattern.
Only mod I did was replaced perches 1/2 “ inboard each side.
72 B 8 3/4 was too wide even for a duster/demon for me.
No issues after that.
Good luck whichever way you decide.
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MOPAROFFICIAL
Oogliboogli
I say he should just weld the rear in straight to the leaf springs themselves at the tubes... clocked for a stationary right turn...then pinch the throttle cable end with some vise grips set @wot...then let her rip. 72nubile might **** hemorrhage his brain booger right out his farthole before flopping dead on the ground..but hey...
QUINN FORBES
Greendemon
The 65-67 B-Body rear can only be forced to bolt up and is wider. The perches are an inch farther apart. Take the time to find an A Body rear, 8 1/4 or 8 3/4 or send your housing off and have someone good shorten the housing and move the perches where they should be.
I say he should just weld the rear in straight to the leaf springs themselves at the tubes... clocked for a stationary right turn...then pinch the throttle cable end with some vise grips set @wot...then let her rip. 72nubile might **** hemorrhage his brain booger right out his farthole before flopping dead on the ground..but hey...
ok so to reset. Lets hook builder89 up best we can!
I wonder if we all agree that a 73 charger 8 3/4 housing will not properly fit “as is” in a ‘70 Duster without some major tire rubbing on the inner rear 1/4 panels?
The 73 will need modifications like perch relocation, axle tubes being cut off and welded back on to A body dimensions, then still needing different/new axles to fit that housing. (IF THE WELDER DID IT PROPERLY)$$$
Some people don’t like to do this.
Understandable.
10” drums or 11” drums? 11”s usually too big for some rims.
Is your Duster small bolt pattern? 5 on 4”?
Any B body axle will be large bolt wheel stud pattern 5 on 4.5”
builder89 needs an A body $$$ or a B body from ‘65 to ‘70 that we know will work on Duster/Demons (not darts or valiants).
A’s are getting like hens teeth nowadays hence the price.
B’s up to ‘70 are more readily available and cheaper but all B body axles are large bolt so my suggestion to 89 would be check what centre section is in your ‘73 B body.
is it worth using in your Duster?
sell the ‘73 B housing complete (maybe keep the centre section if you like the gearing) and put that money towards an A body or a B ‘70 (large bolt pattern axles) and earlier that will be alot less work and money for you.
Either will bolt right in with no tire clearance issues.BUT as mentioned the pre ‘70 B body housing perches will be 1” total difference from your centre eye bolts. You decide to cut off the B perches and reweld inboard 1/2” each side (keeping your pinion angle the same!) or pull your springs apart to accommodate the 1/2” on each side.
Your choice, members say its ok for years and others say not recommended, up to you.
Drums for small bolt are getting harder to find and small bolt disc brakes for the front can be a pain in the *** also.
Welcome to A bodys!
The A stands for Aneurysm.
Lots of us have done the large bolt conversion and lots of us still have small bolt (with limited choice of wheels).
Heck!, some of us have both on the same car and keep two different bolt pattern spares in the trunk (not me but i’d do it).
Summarize: 73 charger 8 3/4 doesn't have much to offer you EASILY except the center section.
Whatever you decide to do it will happen.
Breathe and be patient.
We will help.
Here is more info on 8 3/4’s from Mopartsontheweb. Someone here shared with me. Sorry can’t remember after writing this Aaaaaa Aneurysm
Rear Axle
Axle lengths 8 3/48 3/4" Rear End Dimensions
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8 3/4" axle shaft lengths measured from the tip of the splined end
to the outside of the flange:
A BODY
'66-'72= 27 11/16"
B BODY
'65-'67= 28 7/8"
'68-'70= 29 3/16"
'71-'74= 30 5/8"
'71-'73 wagon= 31 21/64"
C BODY
'65-'69= 30"
'70-'71= 30 5/8" (Chrysler & Fury)
'70-'73= 31 21/64" (and '69 wagon)
IMPERIAL (Large Bolt Pattern)
'65-'66= 30 1/8"
'67-'69= 30 5/16"
'70-'71= 29"
'72-'73= 31 7/16"
E BODY
'70-'74= 29 31/32"
A100
'65-'70= 30"
D100
'65-'71= 31 1/8"
'72-'74= 31 21/64
...........................................
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Housing widths, flange to flange
A BODY
'66-'72= 52 5/8"
B BODY
'62-'63= 53 1/4" (And '64 Max Wedge)
'64 = 55 5/8" (Exc. Max Wedge)
'65-'67= 54 1/4"
'68-'70= 54 15/16"
'71-'74= 57 7/8"
'71-'73 wagon= 59 7/16"
C BODY
'65-'69= 56 3/4"
'70-'71= 57 7/8" (Chrysler & Fury)
'70-'74= 59 7/16" (and '69 wagon)
IMPERIAL
'65-'66= 57"
'67-'69= 57 3/8"
'70-'71= 54 3/4"
'72-'73= 59 5/8"
E BODY
'70-'74= 56 31/64"
A100
'65-'70= 56 3/4"
D100
'65-'71= 58 5/16"
'72-'74= 59 7/16"
.........................................
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Rear end widths, drum-to-drum:
A BODY
'66-'72= 57 1/8"
B BODY
'62-'63= 58 1/2" (And '64 Max Wedge)
'64 = 60 7/8" (Exc.Max Wedge)
'65-'67= 59 1/2"
'68-'70= 60 1/8"
'71-'74= 63"
'71-'73 wagon= 64 3/8"
C BODY
'65-'69= 61.75"
'70-'71= 63.0" (Chrysler & Fury)
'70-'73= 64 3/8" (and '69 wagon)
IMPERIAL
'65-'66= 61 15/16"
'67-'69= 62 5/16"
'70-'71= 59 3/4"
'72-'73= 64 9/16"
E BODY
'70-'74= 61 5/8"
A100
'65-'70= 61 3/4"
D100
'65-'71= 63 15/16"
'72-'74= 64 3/8"
........................................
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Spring perch widths (center-to-center)
A BODY
'66-73= 43"
B BODY
'62-'70= 44"
'71-'74= 47.3"
C BODY
'65-'73= 46"
E BODY
'70-'74= 46"
Isn’t there a slight difference in overall width for the A body 8-1/4 vs the 8-3/4?
QUINN FORBES
Greendemon
I think so , my 81/4 is less almost an inch drum to drum
mopowers
Well-Known Member
AbodyTim
Well-Known Member
If you're on a budget, I would look into a Ford Explorer 8.8 swap. Cheap at the pull-a-part, limited slip, variety of ratio's, and easy to narrow to A-body width. Write-up's are available here on the board.
Unless you are a purist and don't mind paying the price for an A-body 8 3/4 that may or may not have the ratio you want.
Unless you are a purist and don't mind paying the price for an A-body 8 3/4 that may or may not have the ratio you want.
The difference in center offset between my original 15 x 6.50 BBP Rallye wheels and my original 14 x 5.50 SBP Rallye wheels is 1/8 inch so the 8 1/4 rear should theoretically be 1/4 longer drum to drum to keep the wheel in the same position in the wheel wells. Just my logic, I don't have an 8 1/4 rear to measure.
The OP asked about "without any modifications".
I told him I have personally installed a 65-67 B body 8 3/4 in a Duster without any modifications to the axle.
mopowers
Well-Known Member
I disagree. While he doesn’t have the other rear end, he can trade what he has for one or just our base it outright.
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