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Mopar 8 3/4 Rear End

Discussion in 'The Hokey Ass Message Board' started by CoronetRTguy, Apr 9, 2013.

  1. CoronetRTguy
    Joined: Dec 26, 2012
    Posts: 826

    CoronetRTguy
    Member

    Hey everyone,

    I found dimensons for the 8 3/4 rear end today and thought I would post them and maybe help someone that is looking for a rear and might have access to some Mopar stuff.

    I'm trying to figure out if a 66 Chrysler New Yorker and a 67 Dodge Polar 8 3/4 rear will work for my T bucket project idea.

    Here they are and I hope this helps someone else out as well.


    Mopar 8 3/4" Rear End Dimensions
    ........................................
    ........................................
    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
    ...........................................
    ...........................................
    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"
    .........................................
    .........................................
    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"
    ........................................
    ........................................
    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"
     
  2. 340HilbornDuster
    Joined: Nov 14, 2011
    Posts: 2,037

    340HilbornDuster
    ALLIANCE MEMBER

    Great List!!!

    Mahalo
    Tommy
     
  3. CoronetRTguy
    Joined: Dec 26, 2012
    Posts: 826

    CoronetRTguy
    Member

    Thanks I have to give credit to the guys over at the Mopar site B Bodies Only.

    I thought this was a good list and could really help someone else.
     
  4. Flingdingo
    Joined: Jun 30, 2005
    Posts: 539

    Flingdingo
    Member

    Also, B/C/E - body brakes will interchange with A - body housings and vice versa, but are a little wider (1/2 inch total iirc). Something to keep in mind if you are dealing with wheel fitment issues
     
  5. CoronetRTguy
    Joined: Dec 26, 2012
    Posts: 826

    CoronetRTguy
    Member

    Thanks, I have the book parts interchange manual for Mopars and right now I can't think of the years.

    Thanks for that info I will keep a look out for those. I seem to run across A body Mopars from time to time.
     
  6. JCShiels
    Joined: Jul 19, 2009
    Posts: 77

    JCShiels
    Member

    A cheap way to use a wide mopar axle on a smaller vehicle is to use Olds Toronado wheels (4 1/2" bolt circle I believe). Saw this setup on a T many years ago.
     
  7. sport fury
    Joined: Jul 25, 2009
    Posts: 593

    sport fury
    Member

    from mopar direct connect manual
     

    Attached Files:

  8. Big_John
    Joined: Mar 28, 2006
    Posts: 334

    Big_John
    Member
    from Upstate NY

    No, the early (pre 73?) A-body is 4" bolt circle and all A bodies have a shorter distance from the axle flange to the housing. That is the brake drum from a b-body will hit the backing plate on an A body.
     
  9. stillrunners
    Joined: Aug 27, 2009
    Posts: 10,593

    stillrunners
    Member
    from dallas

    correct Big John.....thanks all for a great thread.....we were just checking a 9" Ford rear he other day....and no...8 3/4 axles won't fit in one...they're too Big.....
     
  10. Flingdingo
    Joined: Jun 30, 2005
    Posts: 539

    Flingdingo
    Member

    Well hey, I can't be right all the time can I?:D I rechecked my archives and the article I remember mentioned they had the axles custom made to accomodate C-body brakes on an A-body housing.
     
  11. CoronetRTguy
    Joined: Dec 26, 2012
    Posts: 826

    CoronetRTguy
    Member

    So would the Dodge 1967 Polar or 1966 Chrysler New Yorker rear end work under a bucket? Would I have to cut the rear end down?

    I can get it for $100.00 not sure how much for just the trans. The 383 I've been told would be to heavy, but would love to have it maybe for a truck that I want to do as well.
     
  12. 73RR
    Joined: Jan 29, 2007
    Posts: 7,342

    73RR
    Member

    Compared to what? A 383 will tip the scales at about 650lbs depending on what is included.


    As for the rear axle, there are plenty of narrower units than the Mopar and still very suitable for a small open wheeled rig.
    One example is the Exploder 8.8, the 'long' side can be shortened to match the 'short' side then you still use stock axles...
    Dig around and you'll find what you need.

    .
     
  13. dblgun
    Joined: Oct 24, 2009
    Posts: 348

    dblgun
    Member

    The brakes on all 8 3/4's are interchangable and are the same as Dana 60's in Mopar cars as well as 9 1/4's well into the 80's. The difference in width is built into the offset in the brake backing plate. Due to this changing brakes will not cure any wheel fitment issue because the brakes have no effect on the overall width of the rearend. Simply put, the 11'' brakes off a 9 1/4 in a 79 Brougham Wagon will bolt onto the 8 3/4 in your 66 Belvedere, 72 Duster and 69 D100.:)
     
  14. CoronetRTguy
    Joined: Dec 26, 2012
    Posts: 826

    CoronetRTguy
    Member

    To a small block chevy, ford or even a mopar motor. I don't know what the person means to heavy, I didnt understand that.

    I think I did see a ford 8.8 for sale. I'm not above getting something that needs to be cut down.

    Thanks.
     
  15. CoronetRTguy
    Joined: Dec 26, 2012
    Posts: 826

    CoronetRTguy
    Member

    Thank you. I have not seen any 9 1/4s for sale I did see a 8 1/4 I think it was...I'm seeing to many numbers today. Medical coding cl***es is killing me lol.

    I will look at options for 9 1/4 too.
     
  16. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,534

    50dodge4x4
    Member

    An 8 3/4 out of a 67 Polara and a 66 Chrysler are both "C" body cars. The numbers you should be concerned with are the drum to drum width. That is where the wheels bolt onto the axle location. Then you need to consider the wheel width, and the wheel backspacing. The back spacing is how much the surface that bolts against the brake drum sits inside of the rear edge of the rim the tire sits against. Most modern wheels have around a 3 1/2" back spacing, which means the back edge of the wheel lip (that the tire mounts against) is 3 1/2" behind the part of the wheel that bolts against the brake drum. A wheel with a 2" back spacing will have a deep dish appearance when looking at it bolted on the car. A wheel with a 4" back spacing will have a very small dish (like most front wheel drive cars).
    The width of the wheel is the distance between inside the front lip that the tire sits against and the inside of the rear lip that the tire sits against, measured straight across the wheel. Picture your wheels as 2 separate parts, one part that bolts against the drum, and the second part the holds the tire. The part the holds the tire can be a wide as 15" wide, or as narrow as 3 1/2" wide. Within some limitations, the part the bolts to the brake drum can be located at any point on the tire holding part's width, and that location is measured from the back, or inside surface, of the tire holding part. Clearance issues are for you to determine.

    Concerning motor weights, a typical small block Chevy (or Dodge, or Ford) engine, with manifolds, and without belt driven accessories except the water pump, weighs about 550 lbs. Most big block motors are about 100 lbs heavier. FE Fords, big block Olds & Pontiac add another 100 or so lbs, and a Hemi tips the scales in the 900 lbs range. Adding aluminum parts reduces weight (some motors have very heavy intake manifolds and heavy water pump or water pump housings), and adding tube headers over cast iron exhaust manifolds generally reduce the weight as well (some motors have very heavy exhaust manifolds). Gene
     
  17. CoronetRTguy
    Joined: Dec 26, 2012
    Posts: 826

    CoronetRTguy
    Member

    Thank you Gene, that was good info. I'm going to cut and paste this into a file so I can put it in my build book with other info that I'm collecting.
     
  18. Munster Motors
    Joined: Jan 23, 2012
    Posts: 457

    Munster Motors
    Member

    use an 8 3/4 out of an A body
     
  19. CoronetRTguy
    Joined: Dec 26, 2012
    Posts: 826

    CoronetRTguy
    Member

    Yeah that is one that I'm looking for as another member told me to get one of those. I do have some A bodies around here but no one is parting them right now.

    I have a contact that may have one and may just have the motor, trans, and drum breaks and wheels I need. I know I have some truck wheels from a 75 Dodge slant six truck. I need to look and see what rear is in that one. The truck is stored on my grandparents land, it was used on our farm after it was given to my dad for part payment in a paint job before that it was used by the state forrestry.
     
  20. Rocky
    Joined: Mar 3, 2001
    Posts: 17,630

    Rocky
    Classified Editor

    And don't think you can use a pair of fat 70s Imperial axle shafts and have them shortened and resplined. They're tapered and when shortening them you get down past the hardening...you'd need to have the axle shafts re-hardened...Moser woke us up to that when trying to shorten an Imperial 8 and 3/4ths to fit under my brother's Morris Minor. Mosers sold us a good, used pair of Dodge shafts. No sweat.
     

    Attached Files:

  21. ramrod36
    Joined: Mar 20, 2007
    Posts: 164

    ramrod36
    Member
    from Upstate NY

    For two separate projects I have used A Body 8 3/4 rears. Moser has axles available with the 4 1/2 bolt patterns for the A Body rears. For brakes I used everything from a Volare/Aspen from backing plates to drums. That is the setup under my 36 Dodge pick up in my avitar.
     
  22. 73RR
    Joined: Jan 29, 2007
    Posts: 7,342

    73RR
    Member

    Big block exception is the 455 Buick, at about 50lbs more than a generic smallblock and 100 inch benefit. I have never heard anyone regretting using one.
    But Gene, you really got me on the 900lb Hemi deal though....which engine are you thinking of?

    Gary
     
  23. Ya, I though early Hemis weighed in about 700-725 lbs. A 426 Street Hemi weighs about 825.
     
  24. scootrz1
    Joined: Apr 16, 2011
    Posts: 269

    scootrz1
    Member
    from usa

    I use a 8 3/4 out of a B body in my roadster ( i had it already) iwould of liked to use a A body one instead I just added off set cop rims on the rear car handles great and moves along great
     

    Attached Files:

  25. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,534

    50dodge4x4
    Member

    Must be old age or new math. The book (Moper performance ch***is book dated 1981) says: The typical small block (Mopar) weighs around 550 lbs, the B & Rb (383-440) are about 100 lbs heavier (650 lbs). The 426 Hemi adds another 100 lbs (750 lbs), and the old Hemi from the 50s is heavier then the 426. (no numbers given, but I've read someplace the 50s Hemi weighs 50-75 lbs more then a 426 which puts it at 800-825 lbs, if that is correct.)
    Reference to a Buick 455, I know several that can attest to a fairly weak rod & crank. Many of those guys have went to other motors.

    The rear axle out of a Dodge truck (62-93 1/2 ton) is about 62" wheel mounting surface to wheel mounting surface, the same as the late model B body, and the 60s & 70s C body.

    I guess I'm failing to understand why the m***ive search for a rear axle that is 2"-3" wider or narrower then another for use with an open wheel car like a T bucket. Can't that be made up in wheel width and back spacing? I can understand with a narrow enclosed car with limited space (barely, with the ease of narrowing rear axles these days) but with an open wheeled car it seams a bit unusual. Gene
     
    Last edited: Apr 12, 2013
  26. CoronetRTguy
    Joined: Dec 26, 2012
    Posts: 826

    CoronetRTguy
    Member

    Hey Gene,

    It's just me learning this is project will be my first build from the ground up hot rod. I'm used to restoring cars and only using what came on the car originally so I'm just really learning a lot.

    I really want to build a good looking traditional T bucket. When it comes to running gear I feel out of my area. I'm more of a or I should say used to doing body work with how my dad (retired body man) would tell me how to do things.
     
  27. 73RR
    Joined: Jan 29, 2007
    Posts: 7,342

    73RR
    Member


    Gene, wasn't doubting what you possibly had heard or read but these days there is alot of **** on the www and it never goes away. Given the complete and total lack of interest from Mopar I don't know why they even bother to waste ink on the EarlyHemi subject.
    One of these days I will have to take the time to start throwing parts on the scale. There are, of course, huge differences between the various EarlyHemi engines so I'll toss some of everything on the scale.

    .
     
  28. Dane
    Joined: May 6, 2010
    Posts: 1,351

    Dane
    Member
    from Soquel, CA

  29. nhmikel
    Joined: Jun 29, 2012
    Posts: 308

    nhmikel
    Member
    from NH

    Recently acquired 8 3/4 mopar rear narrowed and axles shortened.
    What model & year truck/car do I get the backing plate and drums
    for 11" & 3" w??
    Any tips on ***embly? What chuck (model etc)do you recommend for auto 3:24?
     
  30. nhmikel
    Joined: Jun 29, 2012
    Posts: 308

    nhmikel
    Member
    from NH

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