Help for a rear end setup

Transmission and Drivetrain Tech

  1. Jimmy2Times

    Jimmy2Times Active Member

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    Still digging at what I actually have here 5x4 small bolt pattern and made a thread about going BBP. I want to go dr diff rear disc brake and spring offset with axles so I can try to get a 15 with a 275. Rear is a little wet and really this hole car has to be gone through. It seems like a solid car so I don't wanna hack anything off it and really want a street strip car. I wanted to start with brakes and get the rear end right for new wheels and tires in the future.

    Also looks like the traction bars would have to go? What are my best options here. And do the #s on the side of the rear mean anything? Sorry for the dumb questions.

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  2. 65 Dartman

    65 Dartman FABO Gold Member FABO Gold Member

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    Looks like you have a reasonably desired 8.75 with the 741 pumpkin. You could re-gasket the pumpkin which should take care of your “little wet” issue. Since you want to get Dr Diff LBP axles, time to regasket would be when you pull/replace your current axles. Do a search - there are many threads on this very subject.
     
  3. Jimmy2Times

    Jimmy2Times Active Member

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    So I've gathered a little bit of info here. 741 weakest of the bunch, yes my plan was to do everything at once. But if I have future plans to put some power through this should I be looking into something else? Others say they hold up decent, gearing can be an issue. Just don't want to do anything twice.
     
  4. 65 Dartman

    65 Dartman FABO Gold Member FABO Gold Member

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    Well, Mother Mopar used the 741 behind Max Wedges and Race Hemis in 64 so they seemed to hold up pretty good. Selection of gearing could be an issue! If you planning on putting a decent amount of power through it, then I’d maybe be on the lookout for a 742 Sure Grip since the SG can easily be rebuilt with new clutches unline the 489 which will require special maching of the cones. Just my opinion.
     
  5. Jimmy2Times

    Jimmy2Times Active Member

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    I have been able to find some good info, should have searched a little more before I opened my big mouth. I will have to get my facts straight and compile my questions in a thread one day.

    Guess the answer would be to slide a little more m pool ney over to doctor diff?
     
  6. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    How much power? And better yet, how much traction? If you're just going to run BFG T/A's then you'll probably spin before you hit that 741 super hard. If you're going to run drag radials or slicks then the 741 might not be a great idea depending on your power upgrade plans.

    That 741 case probably doesn't have more than 3.23's in it too, so you definitely want to consider your gearing before you go too crazy.

    While the 742 probably had a clutch style sure grip from the factory, and the 489 likely had a cone style, what you can find now is totally different. No reason you can't put a clutch style sure grip in a 489 case.
     
  7. Jimmy2Times

    Jimmy2Times Active Member

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    Awesome thanks for info.
     
  8. Jimmy2Times

    Jimmy2Times Active Member

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    If I can squeeze it seems like some can with perfect spacing 275/60/15 drag radial

    Plan as of now of looking to go 416 route it the future. Maybe 450ish of course more would be great.
     
  9. Jimmy2Times

    Jimmy2Times Active Member

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  10. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    That would work, the "cone" thing is just the type of the limited slip differential. You can tell Cass whatever you'd like, he can build it with a clutch type, a cone type or even his own helical gear set up differential.
     
  11. Jimmy2Times

    Jimmy2Times Active Member

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    Awesome looks like I have to make a call as his name has come up for literally every I want to do. Disc brakes, axles, spring offset, and now this. Going to read up and keep an eye out, I'm sure for the money I could go a different way. But you get what you pay for.

    Thanks for the help
     
  12. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    Yessir, for that list of stuff DoctorDiff is the only place I'd go.
     
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