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th700r4 to th350 or th400?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Bross82, Jan 29, 2003.

  1. Bross82

    Bross82 1/2 ton status

    Joined:
    Feb 11, 2002
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    Location:
    Spencer, MA
    what do you think of the rebuilt th350 and th400 trannies from summit and TCI? is there a better place to get good already rebuilt trannies at a low price?

    how much more difficult would it be to replace with a th400? in the long run, hopefully only 2-3 years, i plan on swapping in a 454 and adding as much power as possible. so i'm trying to keep that in mind. what adapter(s) would be needed for a th350 and what would be needed for a th400? is there anything else i need to keep in mind that i would need to be upgraded or changed such as the torque converter?

    how well will one of the th350 or th400 trannies hold up with: 305/th700r4/np208/3.08 ? dont plan on this being a long-term setup, but the current axles and gears may need to stay in up to a year.

    thanks for any help,
    matt
     
  2. 8_YOUR_H2

    8_YOUR_H2 1/2 ton status

    Joined:
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    Location:
    Iowa
    The summit transmission only comes in 2wd so you would have to get a 4wd shaft swapped into it and that would require a total tear down since the output shaft is the last thing out. I took out my 700R4 and put in a TH350, The bolt pattern is the same for all chevy transmissions. Just be sure to hook the vacuum modulator up to a full time vacuum port and not a timed port and dont forget to hook up the kickdown cable (opinion varies on that detail)
     

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