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swap th350 for a th400

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 79k20, Oct 16, 2001.

  1. 79k20

    79k20 1/2 ton status

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    what all will be involved with this? the th400 i bought came with the adaptor for my np203 so i got that part covered. but whar else will i need to do. the th400 is a little bit longer than th th350, right? so will my drive shafts need any work. my plan is to swap lower gearsets into it, will make first 3.00 and second 1.57.

    sean

    79 k20(duh) d44, 14bolt, built 350,350,np203,9"lift
     
  2. 79k20

    79k20 1/2 ton status

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    hello, anybody?

    sean

    79 k20(duh) d44, 14bolt, built 350,350,np203,9"lift
     
  3. ken

    ken 1/2 ton status

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    You will need a 32 spline input shaft for your 203, as your present TH350 versioned 203 has a 27 spline input and is not compatible with the TH400's 32 spline output. Also, you will have to lengthen and shorten your d/shafts.

    ken
     
  4. 79k20

    79k20 1/2 ton status

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    thanks for the info.

    sean

    79 k20(duh) d44, 14bolt, built 350,350,np203,9"lift
     

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