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700r4 to a tb350

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by cinchjeancowboy, Dec 8, 2003.

  1. cinchjeancowboy

    cinchjeancowboy Registered Member

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    How hard is this to do. My buddy said it was pretty easy. Said that you can buy a kit for about a $150 bucks it the 350 bolts up just fine. I am sick of this 700r4 and the $700 bucks to get a new one plus my labor. /forums/images/graemlins/1zhelp.gif If I go the 350 way it will save me about 300 bucks. And I know I will lose overdrive
     
  2. MTBLAZER89

    MTBLAZER89 3/4 ton status GMOTM Winner

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    I am getting ready to do this swap too. Advance Adaptors sell's the adaptor and output shaft for around $200 I believe to keep your 208/241. You need the new longer output shaft for the tranny.I just bought a TH350 that had a 208 so mine is just a direct bolt up. I'm not sure on driveshaft issues yet, but I am pretty sure they will be minimal /forums/images/graemlins/thumb.gif
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    What year 700r4, the later ones were stronger with all the upgrades that took 7 years to figure out. You will lose not only overdrive but your first gear wont be as low either!
     
  4. k5guyva

    k5guyva 1/2 ton status

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    I agree with Pauly. Actually you can build a serious 700r4 for just a little more than a 350. And you get a really low first gear and an overdrive too. A 700r4 also has a lockup torque converter.
     
  5. R72K5

    R72K5 Banned

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    alot of the 80s th350 are lockup converter, and 700r4 are good 87-up.

    you could probably find an adapter for th350 to whatever T-case you have for less than 150 i would think, i assuem you have 208 case
     
  6. MTBLAZER89

    MTBLAZER89 3/4 ton status GMOTM Winner

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    You need the adaptor and a longer output on the TH350 othewise the splines don't engage enough. My Th350 came from 80-82 (I think) with the 208 which saves some of the work /forums/images/graemlins/thumb.gif other than that call AA and see what they want for the package
     
  7. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    I'm with keeping the 700. By the time you buy the kit and swap it over you would probably be pretty close to what a rebuilt 700 would cost. Your 700 is a great tranny, it just needs to be rebuilt and I'm guessing it's an early one so some upgrades will really help. One thing that a lot of people forget is that a 700 is based on a th350. A LOT of the parts in a 350 can be found in the 700 and one of the weakest links in an early 700 is the adopted th350 rear planetary, this is known for failure. I had an earlier 700 that is an 85' box. I have all KINDS of upgrades in mine from late model 700/4L60&80/corvette parts. My new 700 can easely handle 400 to 500 HP, much more than a stock 350 and I only paid $1,300 all rebuilt and installed. /forums/images/graemlins/thumb.gif When you start modifying any tranny from the inside it's going to get expensive.
     
  8. k5guyva

    k5guyva 1/2 ton status

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    I did the same kinds of upgrades on an '86, and it cost me about $1200. Now, I can beat most of the rice burners off the line when the light turns green. And that's with a tired 305. Imagine what a new 350 can do. Factor in that the K5 is about 2-3 times the weight, and that's really impressive.
     
  9. btolenti

    btolenti 1/2 ton status

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    Where did you guys get your trannies??? Bowtie Overdrives???
     
  10. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    custom built at a very knowledgable local shop. /forums/images/graemlins/thumb.gif
     
  11. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    custom built be... ME
     
  12. k5guyva

    k5guyva 1/2 ton status

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    Mine was built local too. But I told them what I wanted. /forums/images/graemlins/thumb.gif
     

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