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I need help with transmission

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 83k5dan, Aug 21, 2000.

  1. 83k5dan

    83k5dan Registered Member

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    I have an 83 K5, with a 700r4 transmission. I am putting a 400 horsepower engine in my truck. I was told that the 700r4 will not hold up to that kind of power, and that I should get a turbo 350 transmission. I am just wandering if it will bolt right in or will I have to get some kind of install kit. Please just let me know something as soon as possible. Thanks
     
  2. Sparky

    Sparky 1/2 ton status

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    Personally I would build the 700r4 up. It is a piece of crap, but it can be built to last. (Even with that kind of power) As far sas the TH350 gos, I am pretty sure it will bolt right in. I think you will have to move the t-case cross member, and maybee get new drive shafts.

    78 K-5
     
  3. BigBadBowTie

    BigBadBowTie 1/2 ton status

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    I too would build the 700R-4. I have a fresh 383, with over 400 ponies & my stocker seems ok. Do a search on this forumn there are a few really good compaines with kits. And a few useful websites or info

    <font color=purple>Rick
    86 K-5</font color=purple>

    http://www.BigBadBowTie.ColoradoK5.com
     
  4. sosamantx

    sosamantx 1/2 ton status

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    I just meet a guy this last week that has a sweet looking (I mean clean) 60 something Nova, with a (not sure of the motor) blower, and about a 3 inch exaust. I am talking some serious horsepower. He says he has run a best of (with exhaust) 10.81 with a 700R transmission. He says that het originally had the transmission for 4 years before he had to do anything for it. I have been planning a conversion for my 74 Nova and was wondering if it would stand up to my sb350. Well he answered my question for me. - Steve

    Steve Sosa a.k.a. "sosaman"
    http://sosaman.home.texas.net/carpics.html
     
  5. talldogg

    talldogg 1/2 ton status

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    I've been doing my homework for the same reason. I want a 700 behind my 454! From what I gather the B and M transkit includes all the up grades to strengthen the 700. From there I plan on getting a larger capacity pan and a cooler. I'll probably put a fan on the cooler too. I believe in over-kill. I do A LOT of freeway driving so I need the OD. The 400 would be the logical choice, but I'm going to give the 700 a shot. FYI the 700 is pretty much the same tranny as the 4L60E and they put that behind the LT1, so it should be pretty strong.
    Check this out
    http://www.700r4.com
     
  6. Emmettology 101

    Emmettology 101 3/4 ton status

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    If this helps, they are putting the smaller and weaker 200r4 or 4r which ever it is, behind 455 pontiacs since there isn't a 700r4 that will bolt up. I thought that was kind of weird since that 200 is a weak tranny, but they are having them built and are withstanding the high HP and Torque numbers from Pontiacs! Just to give you an example, my borthers HO 428 puts out 390 HP and around 450+ torque stock.

    Mike
    1982 GMC Jimmy - <font color=green>Emmett</font color=green>
    http://emmett.coloradok5.com
     
  7. 6.2Blazer

    6.2Blazer 1/2 ton status

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    It is pretty rare to actually break a 700r4. The failures are caused by a lot of heat which burns up the clutches. I would install a large cooler and a temp gauge to make sure this doesn't happen. Another key to keep the 700r4 alive is to run it in Drive, not overdrive, around town and on back roads. Only shift into overdrive while cruising on the flat, long stretches of road at higher speeds (55 or above). This keeps the tranny from constantly shifting between drive and overdrive which will burn up the 3-4 clutch pack really fast.
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    The 700R4 and the 4L60 are the same tranny. GM just changed the designations. I can't remember what year they started with the new designations though.

    [​IMG]
     
  9. talldogg

    talldogg 1/2 ton status

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    6.2,
    Thanks for the boost of confidence. I do A LOT of freeway driving, but I was hesitant about the strength of the 700. I have available to me a 700 and the matching 208 (I know it's AL) for $200, plus the driveshafts are still on the truck so I'd be getting everything to perform a relatively simple swap into my 75. I'm getting really psyched!!!!
     
  10. River

    River 1/2 ton status

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    They made TH700R4 from `87- just as strong as the TH350 when you upgrade your TH700R4 whit B&m or TCI it will be real strong. From `91 and later they renamed the TH700R4 to 4L60 and from `92 it became the electronic version 4L60E.

    Greetings from Amsterdam,

    River `90 K5, 350, TH700R4, NP241, "33, 3.08, 10 bolt F, 10 Bolt R
     

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