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NP203 to NP208 swap

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by rich, Oct 9, 2001.

  1. rich

    rich 1/2 ton status

    Joined:
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    Location:
    central NC
    My friend has an ailing NP203 in his Jimmy and would like to replace it with an NP205. However, NP205's for TH350's are hard to find around here, and the driveshafts to fit them in a Blazer are even harder to find.

    Is an NP208 another option? I know that the NP205 is the strongest, but an NP208 is plenty strong for this application. I like the lower gearset of the 208, and 208's are more plentiful than 205's. But most 208's seem to be behind TH700's, not TH350's.

    Were there NP208's offered for TH350's? If so, what years?

    What is involved in bolting a 208 onto a TH350 that used to have a 203 attached? Is the TH350 output shaft length the same for both cases?

    Thanks!

    Richard
    Raleigh, NC
    '90 K-5 Blazer - stock, daily driver
    '76 K-5 Blazer - 14-bolt FF, 4.10's, locked front and rear, 36's, SM465/NP205
     
  2. The only year with the 208/350 combo was 81.You have to change the output shaft but its not that hard.Advance Adapters makes one or you can get one from a tranny parts supplier which would be alot cheaper.Good Luck
     
  3. rich

    rich 1/2 ton status

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    Location:
    central NC
    Thanks for the info!

    A couple of further questions:

    Since the NP208 for the TH350 was only offered in '81, can I use the NP208 off of a TH700? I assume the adapter for the TH700 is different, isn't it? Is the input gear the same?

    Unless I can use an NP208 off a TH700, it looks like I'll probably have more luck finding an NP205 than an '81-only NP208 for a TH350.

    What exacly is involved in swapping the output shaft of the trans? I always thought you had to disassemble the trans to swap output shafts?

    Thanks!

    Richard
    Raleigh, NC
    '90 K-5 Blazer - stock, daily driver
    '76 K-5 Blazer - 14-bolt FF, 4.10's, locked front and rear, 36's, SM465/NP205
     

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