Change 8.25 rear axle to big bolt pattern

Early A-Body Discussions

  1. briwill70

    briwill70 Well-Known Member

    Messages:
    120
    Likes Received:
    40
    Joined:
    Feb 2, 2020
    Location:
    Portland, Oregon
    Local Time:
    11:30 PM
    I've got a 65 Dart that has a post '73 7.25 rear end. I found a 8.25 rear axle from a 72 scamp that has a better rear gear ratio. How hard is it to convert that to the big bolt pattern? Is it hard to find axles?
     
  2. 65 Dartman

    65 Dartman FABO Gold Member FABO Gold Member

    Messages:
    12,188
    Likes Received:
    3650
    Joined:
    Sep 24, 2006
    Location:
    Strasburg, VA
    Local Time:
    2:30 AM
    The 8.25 should already have the big bolt pattern axles
     
    • Agree Agree x 6
    • SGBARRACUDA

      SGBARRACUDA ROY FABO Gold Member

      Messages:
      19,545
      Likes Received:
      7953
      Joined:
      Dec 7, 2006
      Location:
      PLANT CITY FL. and PERRY GA.
      Local Time:
      2:30 AM
      Yes if it is a 8.25, it will be BBP.
       
    • str12-340

      str12-340 FABO Gold Member FABO Gold Member

      Messages:
      1,770
      Likes Received:
      1038
      Joined:
      Dec 26, 2012
      Location:
      Vashon, WA
      Local Time:
      11:30 PM
      No 8.25 rears until 1973. 8.75 in 1972, so this axle (which would be SBP). Now if this is a whole 8 3/4 rear and and you swap it for the 7.25, that would be worth your while... there are several sources for big bolt axles for 8 3/4 rear ends. Would it come with the brakes shock plates, brackets? All different from 7.25 to 8.75, and you would get better rear brakes to boot if you made this swap.
       
      • Agree Agree x 1
      • McMopar1

        McMopar1 New Member

        Messages:
        1
        Likes Received:
        0
        Joined:
        Dec 21, 2020
        Location:
        North Carolina
        Local Time:
        2:30 AM
        What are the sources?
         
      • 33IMP

        33IMP Well-Known Member

        Messages:
        851
        Likes Received:
        864
        Joined:
        Jul 3, 2020
        Location:
        Taxifornia, soon 2b arizona
        Local Time:
        11:30 PM
        An 8 3/4 would be a dropout center section, an 8 1/4 has a bolt-on rear cover. First thing to do is decide what you are looking at. (An a-body 8 3/4 is worth three times what an 8 1/4 is worth).
         
      • volunteer

        volunteer Well-Known Member

        Messages:
        101
        Likes Received:
        50
        Joined:
        Jun 20, 2018
        Location:
        British Columbia
        Local Time:
        11:30 PM
        So what are the primary options to 'upgrade' (8.75) to BBP? I can think of redrilling original flanges or - aftermarket axles. Pros and cons to each of these? Sources or suppliers? Costs? :(
         
      • 66'GTRob

        66'GTRob Member

        Messages:
        20
        Likes Received:
        4
        Joined:
        Jun 11, 2012
        Location:
        Tucson,Az
        Local Time:
        11:30 PM
        I ended up using the Yukon axles for my early A body 8.75 as well as 72 Monaco 11 inch rear backing plates and drums.
         
        • Like Like x 2
        • str12-340

          str12-340 FABO Gold Member FABO Gold Member

          Messages:
          1,770
          Likes Received:
          1038
          Joined:
          Dec 26, 2012
          Location:
          Vashon, WA
          Local Time:
          11:30 PM
          Yukon are great for a typical high performance street cars. Moser are the best but more expensive. Build for your dream engine if you are going to keep this car around, it's most expensive if you buy them twice...
           
          • Like Like x 1
          • toolmanmike

            toolmanmike FABO MODERATOR Staff Member FABO Gold Member

            Messages:
            58,132
            Likes Received:
            45221
            Joined:
            Jan 18, 2006
            Location:
            Iowa
            Local Time:
            1:30 AM
            Dr Diff has what you need (after you figure out what you have)
             
            • Like Like x 1
            • briwill70

              briwill70 Well-Known Member

              Messages:
              120
              Likes Received:
              40
              Joined:
              Feb 2, 2020
              Location:
              Portland, Oregon
              Local Time:
              11:30 PM
              It was a 8.25 with sbp but it sold. The search continues.
               
            • toolmanmike

              toolmanmike FABO MODERATOR Staff Member FABO Gold Member

              Messages:
              58,132
              Likes Received:
              45221
              Joined:
              Jan 18, 2006
              Location:
              Iowa
              Local Time:
              1:30 AM
              Mopar_rear_id.jpg
               
            • SGBARRACUDA

              SGBARRACUDA ROY FABO Gold Member

              Messages:
              19,545
              Likes Received:
              7953
              Joined:
              Dec 7, 2006
              Location:
              PLANT CITY FL. and PERRY GA.
              Local Time:
              2:30 AM
              No such thing as a factory 8 1/4” with SBP.
               
              • Agree Agree x 4
              1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
                By continuing to use this site, you are consenting to our use of cookies.