9 1/4 Diff strength

Engine, Trans & Driveline

  1. m79ded

    m79ded Well-Known Member

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    Hi All
    Happy belated New Year to all and stay safe.
    I originally had a 9.25 diff in my 79 magnum and many years ago I found a Dana 60 from a 71 GTX which bolted right up and even eliminated the ISO stuff, the reason was because I was racing the car as well as car show duty and all was good until the Sure grip needs to be replaced because of the use and that it's 50 years old. And I have a few Mopar buddies asking to sell it for their 71 B-Body restorations. I was thinking of putting back the 9.25 diff but was unsure of the 612HP 625tq levels my 451 makes, car runs 11.50's now. Would the 9.25 be good enough? C Clips are a concern? I haven't worked with that diff extensively to know. Any insight would be greatly appreciated
     
  2. pnora

    pnora Well-Known Member

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    My opinion stay with the Dana. The 9 1/4 rear is a decent unit. With that being said in the long run you will be happier and win more races keeping the Dana.
     
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    • slepr1

      slepr1 Well-Known Member

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      Unless you are a gambling man stay with what works and hasn't broken yet.
       
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      • 493 Mike

        493 Mike FBBO Gold Member FBBO Gold Member

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        Automatic? Trans brake? Std. trans? 9 1/4" should live a long time behind a automatic. The C clips may be eliminated if a kit exists to perform that function.
        Mike
         
      • Kern Dog

        Kern Dog FBBO Gold Member FBBO Gold Member

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        The GM axles are the ones to worry about in regards to the C clip failures according to Mopar Action magazine's Rick Ehrenberg.
         
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        • m79ded

          m79ded Well-Known Member

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          Automatic no trans brake 9 1/2 " 3600 Ultimate converter 1.63 60ft SS springs, Full street car that visits track often and car shows every time it gets, C clips came to mind because GM guys were yacking all about it.
           
        • m79ded

          m79ded Well-Known Member

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          So you haven't heard issues with the Mopar C-Clips?
           
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          • rumblefish360

            rumblefish360 Well-Known Member

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            The 9-1/4 are still in use under RAM trucks.
            Look to the RAM truck guys and see what there doing.
            (And boy are some of these guys DOING IT!)
             
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            • Kern Dog

              Kern Dog FBBO Gold Member FBBO Gold Member

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              From what I have read, Mopar used a better design and used it for 50+ years!
               
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              • 33 IMP

                33 IMP Well-Known Member

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                I would ask enough for your precious date-code correct axle from the restorers, to cover the cost of a new strange s60. They get their gotta-have-it axle, you get a new, better piece!
                On the other hand, theres not much wrong with a 9 1/4, other than poor gear ratio choice and availability, and the c-clips. The c-clips can be fixed with custom axles, and installing 8 3/4-dana ends. Really the only thing wrong with c-clips is, if the axle breaks, the stub and tire exit the vehicle. Good axles, even with c-clips can solve that problem too.
                I personally dont think 1.50 60fts stretch a properly built 9 1/4 at all.
                 
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                • 66Satellite47

                  66Satellite47 FBBO Gold Member FBBO Gold Member

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                  The 9 1/4" is certainly a stout piece. But a Dana will hold up your level of power for a long, long time. You already have a Dana installed, why take a small step backward? The weight difference is minimal. I expect you would find a good buyer for the 9 1/4 and could use the funds to upgrade the Dana to an indestructible unit.
                  BTW, the GM C clip stuff is just plain inferior to the Mopar stuff, so don't pay attention to those guys.
                   
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                  • Bighead440

                    Bighead440 Well-Known Member

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                    Hey, sell ME that crappy 9.25" Magnum rear for my '71 Satellite Sebring (now 8.25")!!! I'm serious! :)
                     
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