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Squarebody Differentials.

Discussion in 'Differential & Driveline' started by HotRodPC, Jan 27, 2011.

  1. bucket

    bucket Super Moderator Staff Member

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    Right, no K30's before '77. IIRC, it even says "The new K30" in the '77 brochure.
     
  2. 4thgentruck

    4thgentruck Full Access Member

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    Ok this may be a dumb question but what does corporate mean? And what would my 12 bolt out of my.77c10 be?. It origionally had the inline 6 in it.
     
  3. HotRodPC

    HotRodPC Administrator Staff Member

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    Not a dumb question. It's GM Corporate. Meaning GM made their own. It's not a Dana brand, or Eaton brand like other Truck manufactures use. Your 12 bolt will be a GM Corportate Truck rear end. Probably the best choice for a stock to mild performance powertrain on street tires.
     
  4. 4thgentruck

    4thgentruck Full Access Member

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    Oh ok i got you. Thats why I love this forum constantly learning stuff. Esp right before my ground up resto. I know you do alot of commenting on alot of post and quite a few of mine. Ty
     
  5. Rollin_Thunder

    Rollin_Thunder Full Access Member

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    So how much HP and TQ can a stock 14 bolt corporate handle? I'm planning on a 600 HP 1,000 TQ Cummins.
     
  6. HotRodPC

    HotRodPC Administrator Staff Member

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    Go For it !!! Try to break it. Let us know if you can !!!
     
  7. HotRodPC

    HotRodPC Administrator Staff Member

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    Doh, Wait a minute... Are you talking Full Float of Semi Float?? Go with the Full Float 10.5 inch.
     
  8. Driver4r

    Driver4r Full Access Member

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    What 12bolt carriers can hold up to 4.88s?
     
  9. HotRodPC

    HotRodPC Administrator Staff Member

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    Are you asking as in what brand, or what the cut off is for gear ratio? All brands will hold up to 4.88 gears.

    Usually in 12 bolts in both Passenger Car and Truck 12 bolts, it's going to depend on the the deck height on carrier. In a Truck, you're probably looking for a 3.73 and up, as in up numerically, but lower in gear ratio. All depends on where the carrier carrier break is. For 12 bolt trucks there is 3 different carriers, and also for 12 passneger cars there is 3 more carriers.
     
  10. Rollin_Thunder

    Rollin_Thunder Full Access Member

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    Ok. I'll give it a shot. Are full floating stronger?
     
  11. HotRodPC

    HotRodPC Administrator Staff Member

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    Sure enough. Go ahead. Just do it. Try to break it. It'll hold up just fine. Provided it's in good shape, and most are up to about 500,000 miles or more if kept full of good oil, you'll break a transmission or transfer case before you break the rear end in a 14b Full Floater. Yes, the Full Float is stronger. About equal to a Dana 70.
     
  12. Rollin_Thunder

    Rollin_Thunder Full Access Member

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    Well that's good to know. I'll have to make sure it's a full floater.
     
  13. HotRodPC

    HotRodPC Administrator Staff Member

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    If it's a K30 then it already is. 3/4 ton came with either 14bolts in the 80's.
     
  14. elstm3

    elstm3 Full Access Member

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    well i would try to avoid the gov-loc diff in the 14 bolt. get an open diff and get a TAD
     
  15. HotRodPC

    HotRodPC Administrator Staff Member

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    I agree. I'd TRY to avoid the G80 Gov Lok aka Gov Bomb. But, if it's what you have right now, then I'd just go with it. The Gov Lok in 14B Full Floats is apparently stronger than the other Gov Lok models. And when the Gov Lok breaks, you've lost your locking diff feature, but you're not stranded with a broken gov lok. It'll work like a standard open diff. Bad thing about the Gov Lok, it is what it is and you can't install your own limited slip or locker or your choice without swapping to an open carrer first.
     

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