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4bt in a 1978 Blazer

Discussion in 'The Garage' started by crawlink5, Apr 20, 2006.

  1. crawlink5

    crawlink5 1/2 ton status

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    Location:
    Spring, TX
    1978 Chevy Blazer - Bonanza Edition
    1986 Cummins 4BT rebuilt

    4 wd NV4500 rebuilt from GearTechHD.com
    w/hyd clutch
    NV to 465 bellhousing with no adapter - machined at GearTechHD.com
    11" clutch and pressure plate for BB chevy
    Flywheel from Avant Salvage
    pilot bearing

    np205 rebuilt from GearTechHD.com - twin stick
    NP to NV with no adapter - machined at GearTechHD.com

    14bff rear 4.56 detroit with disc brakes
    d60 front 4.56 open

    Hydro boost from 1985 Blazer w/diesel

    a 1" inch body lift would be nice but not absolutely necessary. A 5.5" spring lift in front and a 4.5" shackle flip in rear. the lift is necessary due to height of motor. No hood cutting but it is about 1/2" from hood.

    26+ mpg highway
     
  2. sweetk30

    sweetk30 professional hooker Premium Member

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    and your point is what?:confused:

    no pics of links to see it. sounds good with the specs but we want pics. :mad:
     
  3. crawlink5

    crawlink5 1/2 ton status

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  4. u2slow

    u2slow 1/2 ton status

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    Why not a 12"? Fits on the same flywheel as the 11". Unless the clutch size is restricted somehow by the engine or starter. :thinking:
     
  5. crawlink5

    crawlink5 1/2 ton status

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    I am pulling it out this coming weekend - so I'll have to remeasure. Maybe it is a 12. But, I didn't know the 12 would fit same as an 11.
     
  6. diesel4me

    diesel4me 1 ton status Premium Member

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    MIGHT fit...

    Some of the cast aluminum bellhousings with no inspection cover wont fit over a 12" clutch pressure plate..:doah:

    Not the end of the world though..an 11" clutch has nearly the same surface area as a 12" does...even a 10-1/2" disc has more area than you think..its lining goes closer to the center than any of the other sizes..

    I ran 3 12" clutches in my 72 K5 ,and all 3 of them failed in short order..the 3 finger pressure plates all lost one finger,and they would no longer release!:doah:

    ..I finally got sick of pulling the SM465 and NP205 out ,and used a diaphram style 11" centerforce clutch my friend gave me from his drag car that got totaled after only 4 runs down the 1/4 mile..never gave me a lick of trouble,and my left leg quickly shrank back to its normal size..:p: --those 3 finger 12" pressure plates sure had a high pedal effort..:crazy:
     
  7. u2slow

    u2slow 1/2 ton status

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    If its a truck bellhousing (5.125" index, i.e. for SM465), and a 168-tooth flywheel, either the 11" or 12" can be used.

    I've used the 11" on L6's, and 12" on the V8s - all were diaphragm type.

    I haven't measured to calculate the actual surface area, but the 12" comes with the larger engines and higher GVWRs.
     
  8. Brians89K5

    Brians89K5 1/2 ton status

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    This is exactly what I want to do with my truck when my 350 finally craps out. Although I was thinking of using a newer cummon's from a 1 ton truck. I just gotta figure out how to get CA smog to allow me to do it on my 89. :-(Badass my friend. I am quite jealous!


    ~Brian
     
  9. crawlink5

    crawlink5 1/2 ton status

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    That is the bellhousing I have. No inspection cover. But IIRC, looking at the pressure olate I don't think it could have gotten any bigger. I never measured it - I just assumed 11"
     

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