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CAN SOMEBODY OUT THERE TELL ME WHATS THE CORRECT WIDTH ON A STOCK A BODY AXLE? I AM PUTTING TOGETHER AN 8 3/4 ON MY 72 DEMON.THE HOUSING CAMED OUT OF A 70 DART,STOCK NO MODIFICATIONS ON THE HOUSING?I GOT A 70 CENTER SECTION #489 WITH ITS ORIGINAL SURE GRIP POSI? I HAD SOME AXLES FROM YUKON 28'' INCHES BUT WERE A LITTLE BIT LONGER LIKE 1''INCH TOO LONG? NOW THEY ARE TRASHED? WHAT WOULD BE THE CORRECT AXLE WIDTH FOR AN A BODY 8 3/4??...PLEASE HELP..SOMEBODY.....
 

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..THE SITE FOR SOME REASON DID NOT WORK....ANY OTHER ASSISTANCE ,COMMENTS WOULD BE GREATELY APPRECIATED,SOMEBODY ALSO TOLD ME ABOUT THE METAL PIECE ON THE CENTER OF THE POSI UNIT THAT NEEDED TO BE REMOVED IN ORDER TO BE USED WITH THIS AXLES.....ANY BODY....HELP
 

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..THE SITE FOR SOME REASON DID NOT WORK....ANY OTHER ASSISTANCE ,COMMENTS WOULD BE GREATELY APPRECIATED,SOMEBODY ALSO TOLD ME ABOUT THE METAL PIECE ON THE CENTER OF THE POSI UNIT THAT NEEDED TO BE REMOVED IN ORDER TO BE USED WITH THIS AXLES.....ANY BODY....HELP
Sounds like someone is refering to the "thrust block".Mopar muscle did a build on a rear using longer axles and stock tapered roller bearings claiming the are better than "green" ones for street use.It had some good points.Try searching mopar muscle for that build.It was within the last few years.
 

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I heard Yukons come a little long for the A body. Contact DoctorDif. He is a Yukon dealer and very helpful
[email protected] (406)883-4772
I run the Yukon axles and green bearing with no issue. I looked on their website and then called Mancini to order them because they are listed as one of their dealers.....
 

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The first measurement is the centre to centre spring pad width of the housing, the second is the total axle width flange to flange.

67 - 72 A body 43.02" 55.60"
62 - 70 B body 44.00" 59.20"
71 - 74 B body 47.30" 62.00"
71 - 74 B body Station Wagon 47.3" 63.4"
That site and those numbers are absolutely WRONG for an A body.

The 62-70 B length is wrong as well! They aren't the same throughout those years, there's at least 3 different lengths 62-65, 66-67, 68-70.

An a body 8.75 is 52 5/8 hosuing flange to flange, 57 1/8" wheel mount surface, using the stock SBP brakes.

Here's a link to correct lengths for 8.75 rears.
http://www.moparts.org/Tech/Archive/axle/16.html
 

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That site and those numbers are absolutely WRONG for an A body.

The 62-70 B length is wrong as well! They aren't the same throughout those years, there's at least 3 different lengths 62-65, 66-67, 68-70.

An a body 8.75 is 52 5/8 hosuing flange to flange, 57 1/8" wheel mount surface, using the stock SBP brakes.

Here's a link to correct lengths for 8.75 rears.
http://www.moparts.org/Tech/Archive/axle/16.html
I was doing a search for something else regarding the 8 3/4 diffs and found this thread. Actually Rob, those numbers are dead on. They are not talking about the flange to flange measurement on that site. They specifically say "track width". Track width is the distance as measured from the center to center of the right and left tire, therefore, those numbers are correct. They were just not what the OP was looking for.
 

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I was doing a search for something else regarding the 8 3/4 diffs and found this thread. Actually Rob, those numbers are dead on. They are not talking about the flange to flange measurement on that site. They specifically say "track width". Track width is the distance as measured from the center to center of the right and left tire, therefore, those numbers are correct. They were just not what the OP was looking for.
You might want to look at what is written on the site, it says Flange to Flange.

Copy and paste from the site referenced.

---------------------------------------------
B - BODY 8 ¾ SWAP INTO A BODY
I keep hearing that B body 8 ¾ rear ends fit into A bodies except that they are a little wider. I have never seen this swap but I wanted to provide the B Body 8 ¾ dimensions verses the stock A body 8 ¾ setup. The first measurement is the centre to centre spring pad width of the housing, the second is the total axle width flange to flange.

67 - 72 A body 43.02" 55.60"
62 - 70 B body 44.00" 59.20"
71 - 74 B body 47.30" 62.00"
71 - 74 B body Station Wagon 47.3" 63.4"
-------------------------------------

The rear track on a 66 Coronet is 58.5, not 59.2
 

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The track width difference is the basically same as the axle F to F and Wheel mount to wheel mount dimensions

f to f 54 1/4 vs 54 15/16

M to M 59 1/2 vs 60 1/8

5/8 or 11/16 however you want to slice it. Basically approximately .625-.7"

Just like there is a POS chart on the web that was published in a mopar book that says an A body rear is 51.400 flange to flange and has 62-70 B body rears all the same length. Both are absolutely incorrect. My buddy shortened a rear to that 51.400 length and man was he pissed when the axles wouldn't go in!

It's all good. Just hate to see people work hard to get stuff together and have terribly inaccurate info to base decisions on.
 

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Yukon axles and length of axle shaft

27 11/16" is what you need for your mopar

All the aftermarket axles use the GREEN BEARING NON ADJUSTABLE bearing.... So you need to remove that button from the center of your carrier as it will make a headache for you.

Yukon axles sometimes come in cut to fit length...You just need a chop saw to make yours correct length if they came 28" exactly. AS long as you have 3/4" to 1" of contact patch in the side spider gear of spline you will be fine.

Best to measure from the button out to the end of flange where the bearing seats and measure your axle shaft the same way mark and cut a 1/8" shorter.

Hope this helps. Jim

J D Race.com
 

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Bare, OEM A-body housings measure 52 5/8" from end to end.

When measured straight, A-body 5 x 4 1/2" conversion axles are 28" from flange to end of spline. You do not need to remove the differential thrust block unless the axles are longer than 28".

This applies only to 5 x 4 1/2" bolt pattern axles which take "big car" drums and backing plates.
 

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That site and those numbers are absolutely WRONG for an A body.

The 62-70 B length is wrong as well! They aren't the same throughout those years, there's at least 3 different lengths 62-65, 66-67, 68-70.

An a body 8.75 is 52 5/8 hosuing flange to flange, 57 1/8" wheel mount surface, using the stock SBP brakes.

Here's a link to correct lengths for 8.75 rears.
http://www.moparts.org/Tech/Archive/axle/16.html

That info cost me $600 about 2 years ago and set me back 6 months so I could save up again. I agree 52 5/8" flange to flange.
 
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