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350 to 400TH Power Lost?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by chaka454, Apr 15, 2002.

  1. chaka454

    chaka454 1/2 ton status

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    Okay here's the deal I opened up my tranny to do the oil change and I found metal pieces wich lead me to believe that my tranny is.... shot! okay if I go with a 400 would I loose any power as far as speed power? I know they are good in the torque department how bout the speed dep. anybody done this swap?
     
  2. rockink5

    rockink5 1/2 ton status

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    You won't loose speed, But you will loose the quickness you can get up to speed. 400's take more power to operate than a 350. Not sure how bad it would be in a truck, but in a car it's a night and day differance. How big were the pieces? Some debris is normal wear. If it's like rocks, that's not good.
     
  3. UNCLE CRACKER

    UNCLE CRACKER 1/2 ton status

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    i have heard you lose around 30 HP when you go to a th400
     
  4. TopOff

    TopOff 1/2 ton status

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    I think you only lose acceleration because of the first gear gearing.

    TO
     
  5. BorregoK5

    BorregoK5 1/2 ton status

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    First gear is slightly taller on a 400, and the stronger components are a little heavier which will absorb a little bit of power from what I've read. But other than the gear difference my experience has been that they perform the same.
     
  6. Blue85

    Blue85 Troll Premium Member

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    With the 400, you gain performance because you are no longer afraid of hurting the transmission with the right foot.
     
  7. chaka454

    chaka454 1/2 ton status

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    Well I did get a significant amount of debri nothing big like chunks or anything like that, they were gold in color for a minute there I thought I struck gold but than I came to my senses, the debri looked like wire brush hair not too long but I did get alot of them, most of it was very little, I still feel the tranny slipping even with the oil change, one of my friends who's a mechanic says he can rebuild my tranny and install it all for $450 (friend ?) I looked around and everybody else wants between $550 - $650 to rebuild it, I think I'm keeping the 350 and just rebuild it, I'll get 6 months warranty on it not bad huh? is the price good?
     
  8. Sandman

    Sandman 3/4 ton status Author

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    Getting it rebuilt and installed for $450 does not sound to bad. I got mine rebuilt right before Moab this year for $300 but I had to put it in myself. Just hang an extra cooler on it for security.
     
  9. chaka454

    chaka454 1/2 ton status

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    I already have a tranny cooler it's pretty big maybe that's why it lasted a little longer thanks for the advise.
     

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