An accurate 8 3/4" rear axle width list

Transmission and Drivetrain Tech

  1. STRorange

    STRorange Well-Known Member

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    Great Axle chart, just one that's not quite right though.
    65-69 C-Body axle housing is very close to E-body at 56 1/2" not 56 3/4" as listed.
    Very easy to mix up as they are almost identical, C's 1/6'' of an inch wider than E's overall.
    Got two of each kind here, so I have checked them VERY carefully lol:rofl:
     
  2. dukeboy_318

    dukeboy_318 FABO Gold Member FABO Gold Member

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    @72bluNblu i know this is an OLD thread I'm digging up here, but is the pinion perfectly centered in the rear axle on the A body 8.75 or is it offset to one side or the other a tad?
     
  3. 66fs

    66fs FABO Gold Member FABO Gold Member

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    Offset but axles are the same length
     
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    • dukeboy_318

      dukeboy_318 FABO Gold Member FABO Gold Member

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      nevermind, if the axles are the same length, I guess it doesn't matter
       
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      • 66fs

        66fs FABO Gold Member FABO Gold Member

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        DrDiff has a nice calculator. You can get a good feel for 8 3/4 rear dimensions. 1 3/16" offset from the calculator

        DoctorDiff Housing/Axle Calculator

        Enjoy
         
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        • dukeboy_318

          dukeboy_318 FABO Gold Member FABO Gold Member

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          thanks!
           
        • hellfirechrome

          hellfirechrome Well-Known Member

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          I’m about to have an eight and three-quarter inch axle professionally narrowed. Is the 52 5/8 inch measurement “flange to flange”, for my early barracuda, the measurement between the flange backs or flange centers? I’ve seen it stated both ways.
           
        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

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          Outside to outside on the housing flanges. And that’s just the bare housing, no backing plates or anything.
           
        • hellfirechrome

          hellfirechrome Well-Known Member

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          Killer. Thank you!!! Came home with three housings, might get 'em all cut!
           
        • Jeff 63ValiantConvertible

          Jeff 63ValiantConvertible Active Member

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          Do you have any information for an A Body 1963 Plymouth Valiant Signet. I am wanting to upgrade from /6 to a 318 and it is recommended that I change the rear to 8 3/4...I have no idea just what I need to make this change...do you know?
           
        • abodyjoe

          abodyjoe Well-Known Member

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          you need the abody 8 3/4, the 8 3/4 shock plates and the right length drive shaft.
           
        • Jeff 63ValiantConvertible

          Jeff 63ValiantConvertible Active Member

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          Thanks for the reply:
          I saw that the 8 3/4 listed here had various lengths, unfortunately my year and body type were t included. Question, are all the 8 3/4 axels for A Bodies the same length?
          Also, my car came with a 904 for /6 if Infind a sb 904, do I have to change the drive shaft?
          Thank You
           
        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

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          All A-body 8 3/4’s are the same width. And /6 904’s and small block 904’s are the same length. So the length of the driveshaft still has to change going to the 8 3/4.
           
        • Jeff 63ValiantConvertible

          Jeff 63ValiantConvertible Active Member

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          have you ever done a slant 6 V8 Swap?
           
        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

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          Yes, for my ‘74 Duster. It went from a slant6/904/7.25 to a 318/904/7.25 to a 340/833/8.75 and is currently a 340/T56/8.75.
           
        • Jeff 63ValiantConvertible

          Jeff 63ValiantConvertible Active Member

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          I have some questions, would you mind answering some?
           
        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

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          Not at all, feel free to send me a message
           
        • pomonamissel

          pomonamissel Well-Known Member

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          thanks . pm
           
        • crackedback

          crackedback FABO Gold Member FABO Gold Member

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          I have a pretty cool spreadsheet I set up that will help with axle lengths and wheel backspace. Minitubbed or not, spring relocation both shackle and into frame. It's for A body cars, 67-75. I didn't have a early A to measure off of.
           
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          • Jeff 63ValiantConvertible

            Jeff 63ValiantConvertible Active Member

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            Thank You for responding, I just can’t find much information for 63’s...I have to find out which 8.75 will work for my swap and also how many splines it should have.
             
          • Jeff 63ValiantConvertible

            Jeff 63ValiantConvertible Active Member

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            Thank You abodyjpe, just saw your post...how do you determine splines and what gears would you recommend for 318
             
          • abodyjoe

            abodyjoe Well-Known Member

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            Spline? Axle splines? Pretty sure all the common year non race are the same. I forget the count to tell ya the truth.

            As for gears it all depends what you are doing. Stock 318 and just a driver I'd say 2:76-2:94.

            More then stock 318 and just around town maybe a 3:23-3:55. All depends on your combo and intended use.
             
          • Jeff 63ValiantConvertible

            Jeff 63ValiantConvertible Active Member

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            i wasn’t sure if I’ll need a 28 or 30 spline and didn’t know if I needed a certain year for upgrading the rear end since 63 Valiant didn’t come with a 8.75.

            My 318 build is going to have budget high performance, So would you recommend the 3.55 gears because I would like to drive to various car shows as well as around town.
            Thanks for your help.
            Jeff
             
          • crackedback

            crackedback FABO Gold Member FABO Gold Member

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            Any of the pumpkins should all be 30 spline axles. There isn't any other set up in passenger cars. The best fit is an A body rear if everything is stock set up. Housings aren't cheap in that variant.
             
          • abodyjoe

            abodyjoe Well-Known Member

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            That's all personal preference.
             
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