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Drive shaft lengths and questions

Discussion in 'Differential & Driveline' started by American_justice, Jul 9, 2019.

  1. American_justice

    American_justice Junior Member

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    Joined:
    Jul 9, 2019
    Location:
    Kerrville tx
    First Name:
    Levi
    Truck Year:
    1983
    Truck Model:
    C10
    Engine Size:
    350
    So I have a 83 long bed custom deluxe and my tranny went out. The turbo 350 I had in it before had a 9 in tail shaft length but I have another one I want to put in it that is a 6 in tail shaft. I know the drive shaft won't work for it but I'm wondering if they even made a drive shaft with this configuration and length in a stock vehicle. I know I can make one custom or have one made but it would be nice if I could go rob one off an old junker or something. So I need a lwb drive shaft that will go to a 6in short tail shaft tranny. The one I have for my 9in is approximately 71 in long. It will have to be longer than that for sure. Anyway thanks in advance
     
    Last edited: Jul 9, 2019
  2. Charlie

    Charlie Full Access Member

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    Location:
    Euless, Texas
    First Name:
    Don
    Truck Year:
    1974
    Truck Model:
    Cheyenne 10 LWB
    Engine Size:
    350/TH350/AC/4 BBL Quadrajet
    :welcome:
     
  3. SquareRoot

    SquareRoot Full Access Member

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    Location:
    Arizona
    First Name:
    Mike
    Truck Year:
    85
    Truck Model:
    K20
    Engine Size:
    350
    Is this a 2wd I'm assuming? A 71 incher....wow! Do you know the diameter of that beast?
     
  4. PrairieDrifter

    PrairieDrifter Full Access Member

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    Joined:
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    Location:
    North Dakota
    First Name:
    Mason
    Truck Year:
    84,79,70
    Truck Model:
    Suburban k10, bonanza k10, c10
    Engine Size:
    350, 350, 350
    My 1970 c10 longbox came with 6 inch tail shaft th350 and had a two piece driveshaft with a hanger bearing right behind the cab.

    Not sure if the squares had two piece driveshafts unless it’s a crew cab or a cab and chassis truck. My 77 c30 cab and chassis has a two piece driveshaft but the thing has a crazy long wheelbase
     
  5. American_justice

    American_justice Junior Member

    Posts:
    6
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    1
    Joined:
    Jul 9, 2019
    Location:
    Kerrville tx
    First Name:
    Levi
    Truck Year:
    1983
    Truck Model:
    C10
    Engine Size:
    350
    Look's like it's 3 1/2 in diameter
     
  6. Craig 85

    Craig 85 Full Access Member

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    Location:
    Grass Valley, CA
    First Name:
    Craig
    Truck Year:
    1985
    Truck Model:
    K30 SRW
    Engine Size:
    454/TH-400/NP205
    I had always heard 72" was max. I did some research and found a 2009 Suburban 2500 with a 78.36" rear drive shaft. It is a 4" diameter with .087" wall thickness. In reading the Dorman description, it includes the slip yoke, so I'm assuming this total length includes that.
     
  7. 75gmck25

    75gmck25 Full Access Member

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    Joined:
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    Location:
    VA
    First Name:
    Bruce
    Truck Year:
    1975
    Truck Model:
    K25
    Engine Size:
    5.7
    There is a shop in San Antonio called Driveshaft Specialists, and they had no problem making a new front driveshaft for my K25, just based on the year and model of truck. My front driveshaft has a cardan joint (universal joint), slip joint for length, and other features, and they got it all right. You might give them a call and ask for recommendations on what to do with your truck.

    I had the work done about 15 years ago, but maybe they still have some old guys who understand the best solution for a squarebody.

    Bruce
     
  8. Preston

    Preston Full Access Member

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    Joined:
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    Location:
    Mechanicsville VA
    First Name:
    Preston
    Truck Year:
    1983,1984,1985
    Truck Model:
    83 c3500 (3) 84 K10’s 85 silverado 68 c10 short bed stepside
    Engine Size:
    454 in 85 dually 5.7 LS in 84 350 in 85
    Good luck been there done that, what I saved on the transmission I spent on the driveshaft plus. I put a th 400 in my long wheel base Silverado. Moral of the story fix the transmission. I ran into other issues with the kick down switches, don’t get me wrong the 400 shifts great but I just didn’t save any money making the swap from 700 to 400. I do believe GM did go to 2piece driveshaft if it was over 72” long
     
  9. Preston

    Preston Full Access Member

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    Joined:
    Jan 25, 2019
    Location:
    Mechanicsville VA
    First Name:
    Preston
    Truck Year:
    1983,1984,1985
    Truck Model:
    83 c3500 (3) 84 K10’s 85 silverado 68 c10 short bed stepside
    Engine Size:
    454 in 85 dually 5.7 LS in 84 350 in 85
    Welcome to GMSB from Virginia


    PS you could also swap the tail shaft
     

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