Moparts

8-3/4 rear end selection question

Posted By: moparbroz

8-3/4 rear end selection question - 09/20/11 01:26 AM

I am looking for an 8-3/4 complete rear-end, or a housing with axels,or if I have to all seperate compenents, etc. As I look though I see ads for small bolt pattern, large bolt pattern, Housing with-out axels, third member only 492 case, 481 case, etc. I am confused!

I have a 1972 Staellite Sebring plus that I am putting a 440/727 combo in (I am removing the 318/904/7-1/4 set-up). My question is what exactly should I be looking for? Bolt pattern? width of axels, case #, sure-grip unit #, ring and pinion set up for daily driver, etc. I know A-body rear won't match up but what about C body or? Any direction would be appreciated!
Posted By: RapidRobert

Re: 8-3/4 rear end selection question - 09/20/11 01:58 AM

Welcome! You'd want an 8&3/4 housing/axles from your body type and non A body 8&3/4's are all BBP and most are the std 10" brakes (some are 11"). check the archives for more info on what bodies use the same axle (width/perch) as yours. Want a 742 case sure grip 3rd member with somewhere from a 3.23/3.55/3.91.
Posted By: Kern Dog

Re: 8-3/4 rear end selection question - 09/20/11 02:02 AM

The simplest way to go is probably obvious: Find an 8 3/4 axle for your model car. ALL B body axles were what is called the "large" bolt pattern. Only the A body 8 3/4 axles came in the small bolt pattern. As far as I have found, ANY 8 3/4 3rd member can physically fit into ANY 8 3/4 housing. They all use the same 10 bolt pattern. Also, in mid 1969, the '489 case 3rd member was phased in and ran until the axle went out of production at the end of the 1974 model year. The ones that had Sure Grip differentials were the Cone type. Great when new, but when they wear out, they are not easily rebuilt. A clutch type SG can be rebuilt though if you can scrounge one. They are NOT being reproduced, so you'd have to find a used one.
Posted By: moparbroz

Re: 8-3/4 rear end selection question - 09/20/11 02:13 AM

Thanks for the information gents. I appreciate it! Now I know what to look for. I was on the right track but just wanted to make sure. The sure-grip info is all new to me though and very helpful. So far my experience on moparts is that there are a bunch of very cool, helpful people here!
Posted By: MoparforLife

Re: 8-3/4 rear end selection question - 09/20/11 02:14 AM

Quote:

The simplest way to go is probably obvious: Find an 8 3/4 axle for your model car. ALL B body axles were what is called the "large" bolt pattern. Only the A body 8 3/4 axles came in the small bolt pattern. As far as I have found, ANY 8 3/4 3rd member can physically fit into ANY 8 3/4 housing. They all use the same 10 bolt pattern. Also, in mid 1969, the '489 case 3rd member was phased in and ran until the axle went out of production at the end of the 1974 model year. The ones that had Sure Grip differentials were the Cone type. Great when new, but when they wear out, they are not easily rebuilt. A clutch type SG can be rebuilt though if you can scrounge one. They are NOT being reproduced, so you'd have to find a used one.

I thought the clutch type sure grip were being repopped. Did they quit. Hope so make my 4 or 5 stash worth that much more.
Posted By: savoy64

Re: 8-3/4 rear end selection question - 09/20/11 03:32 AM

Dont play with B body axles--there are 3 or 4 different widths of axles to get lost in----when you replace an axle shaft you have to buy custom made-----if you go with an A body housing every axle shaft is 28 inches--(no dont use the small bolt pattern axles)-if you want to upgrade you can buy a yukon axle from randys for a little over a hundred dollars--i built a dana 60 A body width for a friend running a 70 roadrunner 440 stroker with a blower and a 833 4 speed----he has been racing the car for 3 years and the yukon axle splines have not migrated (twist) his car is pushing 750 hp-----and dont sweat the small brakes you can put your current brakes on the A body housing----or you can disc it up---8.75 or dana 60 i build only A or C body width because axles are always 28 inches or 30 inches---if you buy 10 sets at a time you get a handy discount and free shipping from randys too----bob
Posted By: moparbroz

Re: 8-3/4 rear end selection question - 09/20/11 03:54 AM

Thanks Bob!
Posted By: Kern Dog

Re: 8-3/4 rear end selection question - 09/21/11 01:59 AM

Quote:

Dont play with B body axles--there are 3 or 4 different widths of axles to get lost in----when you replace an axle shaft you have to buy custom made----



Yeah... GREAT advice if you have loads of cash laying around. A body housings are easily 3 times the cost of a 62-70 B housing.
CUSTOM Axles? Why not REuse the shafts that came in the stock rear end? If they look good and you don't intend to run 400 horsepower on slicks, you'll be fine. Even if you want to upgrade, just order a replacement set in the stock length. You worry too much. I have a 67 B housing in a 67 Dart and I used STOCK 15x7 steel wheels with no interference problems.
Posted By: 446acuda

Re: 8-3/4 rear end selection question - 09/21/11 03:26 AM

yukon make power loks for 8-3/4


http://www.yukongear.com
Posted By: moparbroz

Re: 8-3/4 rear end selection question - 09/21/11 03:27 AM

Bueno!!!!
Posted By: DoctorDiff

Re: 8-3/4 rear end selection question - 09/21/11 03:40 AM

Yukon hasn't made power-locks in years.
Posted By: Kern Dog

Re: 8-3/4 rear end selection question - 09/21/11 04:25 AM

Quote:

yukon make power loks for 8-3/4




Arrrrgh. Man make fire. Yukon make power lock.
Posted By: BeEtLeJuIcE !

Re: 8-3/4 rear end selection question - 09/21/11 04:27 AM

Quote:



Arrrrgh. Man make fire. Yukon make power lock.



...FRANKENberri must-have LOTS of time on his hands ..
Posted By: savoy64

Re: 8-3/4 rear end selection question - 09/21/11 04:51 AM

you may be able to source a truck or van axle at a pickapart--the 2wd are more likely to be posi--ask you racer friends who is cutting down axle housings (one hour labor) source the axles and bearings---you should be able to get what you want for $500----bob
Posted By: rave_12000

Re: 8-3/4 rear end selection question - 09/21/11 04:59 AM

I am familiar with 3 types of 3rd members listed in order of durability: 741 < 742 < 489. Granted, pre 1970 units had the clutch-style (easily rebuildable) carrier, but all carriers will interchange between any and all cases. Gears are specific to each case. Shape of pinion is where you will find the difference in durability due to tapering and lack thereof. If you are doing a moderate 440 auto build, any case will be fine.

new yukon 8 3/4 clutch carrier at:
http://www.yukongear.com/Positractions.aspx

Rear housing selection will depend on how much tire you want to fit under there. Perches can be moved and offset sheackles can be used for clearance.

You are looking at about 63" drum to drum on your car, which is one of the widest. perch to perch, you are 47.3", which is the widest of all. The path of least resistance would be to find the original stock 8 3/4 to match your car. The fender wells are quite large to fit some meathooks under there. But, e body 8 3/4 rears are likely less difficult to find and easier on the wallet? You can move the purchases a bit, but you must watch tire/spring clearance. that is where you might consider the the reloc kit or backspace manipulation with wheels.

I wouldn't get to carried away with new axles...use stock with any 5 x 4.5 bolt pattern. your wheels will fit fine. I don't think there would be a need for an a body rear...again, the rear fender flare is huge.

brakes sizes big and small with stock drums. either will be fine for your application. I believe that the 7 1/4 backing plates should just slide right off and right onto the 8 3/4...viola.

most importantly, don't forget to add oil...and a little sure grip additive.

mike
Posted By: 52savoy

Re: 8-3/4 rear end selection question - 09/21/11 05:20 AM

Quote:

I am looking for an 8-3/4 complete rear-end, or a housing with axels,or if I have to all seperate compenents, etc. As I look though I see ads for small bolt pattern, large bolt pattern, Housing with-out axels, third member only 492 case, 481 case, etc. I am confused!

I have a 1972 Staellite Sebring plus that I am putting a 440/727 combo in (I am removing the 318/904/7-1/4 set-up). My question is what exactly should I be looking for? Bolt pattern? width of axels, case #, sure-grip unit #, ring and pinion set up for daily driver, etc. I know A-body rear won't match up but what about C body or? Any direction would be appreciated!



You need a housing with axles or a complete unit out of a 1971,72 and maybe a '73 B-body will work. E-bodies will bolt in but are over an inch shorter but you could run bigger wheels then.

A-body 55.6" wide and 43" pad width

B-body sedans 62.0" wide and 47.3" pad width
B-body wagons 63.4" wide

E-body 60.7" wide and 47.3" pad width

Posted By: moparbroz

Re: 8-3/4 rear end selection question - 09/21/11 05:07 PM

Scored an 8-3/4 out of a 69 Charger for $225.00. Need a sure-grip unit still and the correct length axels. Stoked that I have the housing though. Going to powder coat. What's the correct finish? It isn't gloss black correct?

Attached picture 6836115-8-75REAR.jpg
Posted By: 52savoy

Re: 8-3/4 rear end selection question - 09/21/11 05:30 PM

You know that won't bolt in don't ya???

1962-'70 measure 59.2" and 44" pad width
Posted By: DoctorDiff

Re: 8-3/4 rear end selection question - 09/21/11 05:54 PM

Once again, Yukon (clutch type) 8 3/4" power-locks have not been available for years.
Posted By: DoctorDiff

Re: 8-3/4 rear end selection question - 09/21/11 06:00 PM

B-body housing specs:

'65-'67: 54 1/4" with 44" perch on center

'68-'70: 54 15/16" with 44" perch on center

'71-'74: 57 7/8" with 47.3" perch on center

***I make a 1 1/4" offset spring hanger/shackle kit that can be used to mount a '68-'70 B-body rear into a '71-'74 B-body.
Posted By: 52savoy

Re: 8-3/4 rear end selection question - 09/21/11 06:01 PM

You talk'n to me???

I got my specs directly from Chrysler...
The only B-body housing that was shorter was the Max wedge..1/2"
Posted By: moparbroz

Re: 8-3/4 rear end selection question - 09/21/11 06:02 PM

I will have to adjust to install. I have all the measurements thanks to you guys.
Posted By: moparbroz

Re: 8-3/4 rear end selection question - 09/21/11 06:05 PM

Thanks for the measurements. I found them also in the tech archive. 3.3" adjustment based on center of the perchs. Thanks!
Posted By: moparbroz

Re: 8-3/4 rear end selection question - 09/21/11 06:08 PM

"Dr. Diff." I want that offset! Send me the info including shipping to 92867 and payment preferene to moparbros@yahoo.com. Thanks!
Posted By: DoctorDiff

Re: 8-3/4 rear end selection question - 09/21/11 06:09 PM

The information you got from Chrysler is incorrect.

In addition...

'63 B-body housing: 53 1/4" with 44" perch on center
'64 B-body housing: 55 5/8"" with 44" perch on center (except max wedge)
'71-'73 B-body wagon housing: 59 7/16" with 47.3" perch on center
Posted By: 52savoy

Re: 8-3/4 rear end selection question - 09/21/11 06:15 PM

The information from Chrysler is the "track" measurement. Yours is axle housing length.

correct?
Posted By: MoparforLife

Re: 8-3/4 rear end selection question *DELETED* - 09/21/11 06:23 PM

Post deleted by MoparforLife
Posted By: DoctorDiff

Re: 8-3/4 rear end selection question - 09/21/11 06:45 PM

E-mail sent.

Thanks,

Cass
Posted By: dogdays

Re: 8-3/4 rear end selection question - 09/21/11 06:46 PM

I just talked to Bil Abel at Western Drivetrain and he said the Yukon Powr-Loks were still on backorder, this makes nearly two years. But, he did get a TrueTrac in the other day.

He also warned me that Randy's had a batch made this year and rejected them all because of material problems. So if you see a new Powr-Lok on the 'bay or other places, it is probably the Randy's reject and you don't want it. Machining problems may be repairable but material problems aren't usually.

R.
Posted By: DoctorDiff

Re: 8-3/4 rear end selection question - 09/21/11 06:51 PM

"Track measurement" varies with housing width.
Posted By: DoctorDiff

Re: 8-3/4 rear end selection question - 09/21/11 07:02 PM

My offset hanger/shackle kit bolts in place of the stock brackets. You do not have to modify the new hangers or the body.

In this application, you can't just "move the spring perch" because the U-bolts would end up on top of the housing end.
Posted By: MoparforLife

Re: 8-3/4 rear end selection question - 09/21/11 07:18 PM

68 C body is very close to a bolt in. In fact many have done it by just tweaking the springs slightly. That is what I used on 75 Cordoba and just modified the perch slightly.
Sorry Doc, You are right I was going the wrong direction on previous post. (Deleted.)
Posted By: terzmo

Re: 8-3/4 rear end selection question - 09/21/11 08:24 PM

go here and it should answer most,if not all, questions

http://bionicdodge.com/Download/Mopar_8_3_4_Rear_End_Guide.PDF
Posted By: moparbroz

Re: 8-3/4 rear end selection question - 09/21/11 09:46 PM

Awesome resource. Thanks!
Posted By: DoctorDiff

Re: 8-3/4 rear end selection question - 09/21/11 10:24 PM

I also stock custom and standard length 30 and 35 spline high-strength axle packages for most 8 3/4" and Dana 60 applications.
Posted By: moparbroz

Re: 8-3/4 rear end selection question - 09/21/11 10:55 PM

Cass- I will probably need more than just the hanger and shackle kit from you. Can you email be a parts explosion of an 8-3/4 housing, axel and suregrip unit so I can dtermine what I will need? Thanks!
Posted By: rave_12000

Re: 8-3/4 rear end selection question - 09/25/11 03:39 AM

why do you need to change axles?? looks like correct ones are still in the housing. use a needle grease gun tip to pack the outer axle bearings. i think i have an extra carrier out in the garage.
Posted By: RobX4406

Re: 8-3/4 rear end selection question - 09/25/11 04:45 AM

Quote:

go here and it should answer most,if not all, questions

http://bionicdodge.com/Download/Mopar_8_3_4_Rear_End_Guide.PDF



That has some REALLY bad info because people don't understand track width versus actual axle width. Track width on all 62-70 B's is not 59.2...

Want a better reference, it's here in the tech archive...

http://www.moparts.org/Tech/Archive/axle/16.html
Posted By: RemCharger

Re: 8-3/4 rear end selection question - 09/25/11 04:58 PM

I believe the 70-71, 72? c body is a nice direct bolt in. A buddy just put one in a 74 charger.

That 69 rearend appeared to have axles in it...
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