Putting a late model 8 1/4 Jeep rear end in a 66 Dart

Transmission and Drivetrain Tech

  1. 66DartGTcville

    66DartGTcville Active Member

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    Hello,
    I have heard / read that you can put a late model Jeep Cherokee 8 1/4 3.55 rear end in the older A Bodies...
    Has anyone done this? Seems like a great way to get rear disc brakes, an upgrade from the 7 1/4 rear in there now and move up to the 5x4.5 bolt pattern.
    What am I missing?
    Thoughts?
     
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    • Professor Fate

      Professor Fate Push the button, Max...

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      The Cherokee rear is about 2 1/2" wider than a stock A body rear. The spring perches are only about an inch wider than the A body, but that's irrelevant since the Jeep rear has the perches on top of the housing for hanging it under the leaf stack. The shock mounts are also welded to the axle.
      Cherokees NEVER came with rear disc brakes, that was Grand Cherokee (only the early Grands, up to '98? Not positive of exact year- had 4 1/2" bolt circle) and Liberty only.
      Maybe use one of those rears? Different suspensions (coil springs, control arms and panhard bars) and different widths yet again.
      So, you'll have to cut all the bracketry off, weld on spring perches at your width while setting an appropriate pinion angle, and get a set of Mopar shock plates and U bolts for 8.25, 8.75, or D60 (no, your 7.25 parts won't work, the axle tubes are a different diameter). Then get some custom offset wheels to make up for the different axle width. And figure out how to adapt the parking brake cables to your car. And have your driveshaft shortened about 1.25-1.5". And if using a Cherokee housing, swapping the GC/Liberty discs onto it.
      Will it fit? A school bus rear end will fit if you're willing to put the time and money into it.
      It's not a bolt in, but can be a viable option depending on your skill set and expectations.
      A much easier option would be to find a later-model A body 8.25 and hardware (bolt-in, except for driveshaft length) and swap the GC/Liberty discs onto it.
       
      Last edited: Oct 13, 2021 at 10:54 AM
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      • oldmopardude

        oldmopardude Well-Known Member

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        I decided to simply narrow a 67 B body 8 3/4 housing, and bought new axles from strange. I could have also narrowed a C body housing as well. there are more of them around.
         
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        • ch1ll

          ch1ll FABO Gold Member FABO Gold Member

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          I believe the big deal about this swap is weight, finding an axle that has an aluminum housing. I looked at my local yard and could not find one. Also the axles I saw looked as weak as a 7 1/4 is. Maybe I didn’t look enough to find the right axle. It all depends on how much power you are putting in front of it and how you are going to use it. My guesstimate would be if you are under 200 rear wheel horsepower and not using race compound tires at the drag strip on a glued track, it would be a good handling cruising car with one. If you are looking for an all out performance rear axle, go with a 9 1/4 (poor mans Dana)out of a dodge pickup truck or a dana 60. These axles will take what you throw at it within reason. Skip over the 8 3/4 all together. They are too pricey for what they are. (My opinion) my junk yard is at $350 for a good working 9 1/4 axle out of a pickup and what it costs to modify it for an a-body is close to a used 8 3/4.
           
        • RustyRatRod

          RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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          Rear disc brakes are nice shiny objects that people think they need on a light A body. If you simply WANT them, because all the magazines and forums say it, that's one thing, but are they NEEDED on a light as a feather A body? No.
           
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          • 66DartGTcville

            66DartGTcville Active Member

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            Thanks for the insights. The rear discs were a bonus actually. I am swapping the 273 for a 360. Nothing too crazy but at the end of the day, the hope would be around 375hp and 365 lbs of torque so the stock 7 1/4 just seems like a bad idea. The strength and bigger bolt pattern were the real goal.
            Thanks for the insights and opinions. Much appreciated.
             
          • 66DartGTcville

            66DartGTcville Active Member

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            I like the idea of the 9 1/4 so that is something to consider. Goal is replacement of the anemic 273 with a mild 360 so an upgrade from stock is needed. Bigger bolt pattern for better wheels and tires is critical but really the car is going to be for weekend ice cream runs with the family so no drag strip. Thanks for taking the time to read and share.
             
          • 66DartGTcville

            66DartGTcville Active Member

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            This might be the easiest and best option, thanks.
             
          • 66DartGTcville

            66DartGTcville Active Member

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            Thank you very much. This was extremely helpful. I had looked at the Liberty rears, that was how I ended up down the rabbit hole.
            I realize that there will need to be some modifications, I will not be doing those, but I have someone who can so that helps.
            The rear discs were a bonus, it was the durability and bolt pattern that I was really hoping for to be honest.
            With a pending power plant swap from the tired 273 to a fresh 360, I wanted something more reliable under the extra power.
            Thanks for your insights and expertise.
             
          • Rockerdude

            Rockerdude Rock n' Roll and A-bodies

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            I've looked into this swap before, I have had a few XJ Cherokees and ZJ Grand Cherokees. Ended up finding an A-body 8.25 and using Liberty disc brakes.
             
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            • 72Duster440

              72Duster440 Well-Known Member

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              If you go with an 8.25 out of a Cherokee. Make sure it is a later model one with the 29 spline axle shafts. The early ones were 27 spline.
               
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              • Professor Fate

                Professor Fate Push the button, Max...

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                The aluminum rear axle is actually a Dana 44A, not a Chrysler 8.25. Can be found in some ZJ and WJ Grand Cherokees.
                 
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                • 67Dart273

                  67Dart273 FABO Gold Member FABO Gold Member

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                  If you are going to put money into an axle, and it is NOT an "original type" Mopar such as 8 1/4--8 3/4 etc, don't discount Ford 9" --I am partial to 3rd member axles as they are much easier to swap ratios

                  And yeah.........You'll have to narrow them unless you find the "Gold mine" of something like a Mustang axle
                   
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