L83 - 8L90 swap

Discussion in 'The Engine Bay' started by WALREC, May 21, 2020.

  1. WALREC

    WALREC Registered Member Premium Member

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    Hey, does anybody know anything about the 8L90? I'm picking up an L83 with factory harness and computer this weekend for the K5 and just realized it comes with the transmission too. from what ive read it is supposed to be a real workhorse. It all came out of a wrecked 2017 Silverado 4x4. My K5 has a 700 in it now which im told is not ideal, so, in yalls opinion (or experience) would it be best to keep them together or use the 700? engine n trans only have 27k miles on them so if they would be viable combo im inclined to keep them together. Besides, not having to hack up the harness and deal with tuning issues from separating them is a big plus. Any thoughts? Thanks!
     
  2. bigblock454

    bigblock454 Clack Clack Clack Premium Member

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    I have reservations on these new fangled transmissions. The 6L90 in my brothers Gabillion dollar Burb only lasted 90k miles and that's with zero towing.

    In stock form the 700s are pretty week, can be built to live behind a small block but it takes the right guy to built it correctly. I'm a big fan of the 4L80E, i have several of them now and have beat the crap of each of them, very strong and have available aftermarket controllers.

    I know that doesn't answer your question, just my thoughts.
     
  3. Fastereddie

    Fastereddie Sorry if I offended you. Not. Premium Member GMOTM Winner

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    Definitely run the 8L90. If you have any questions, hit up Matt at Wicked Wrench Motorsports or Mitchell at Swaptime. Or you can ask me here and if I don’t know the answer I can find out quickly. Your going to really like that setup.
     
  4. WALREC

    WALREC Registered Member Premium Member

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    Thanks guys, I guess the only question I can think of now is,, will I need to flash the ecu? ive read conflicting information on this. but with things like ABS and traction control (among other things) my K5 hubs obviously wont communicate w ecm so im sure that would piss off the computer. ive read about stand alone harnesses, complete ecm/harness kits, sending off ecm for tune, so im not quite sure what to expect,, except its not gonna just drop in hook up and run fine. im an old school 350 guy, im just starting to learn about this new shit, and im certain its gonna be an expensive education. im sure I will have many more head scratching moments next week when it goes in. thanks again
     
  5. WALREC

    WALREC Registered Member Premium Member

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    Well got word from the guy today he sold the engine to someone else. Guess its back to huntin.
     
  6. Fastereddie

    Fastereddie Sorry if I offended you. Not. Premium Member GMOTM Winner

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    Bummer
     
  7. WALREC

    WALREC Registered Member Premium Member

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    Yea it does kinda bum me out. It took a looooonnnnng time to decide to go LS,, i like my 350s, but when i finally did make that decision i was excited to learn the ins n outs of the gen5s. It was the unknowns i suppose that made me hesitate,,, well that and all the computer shit. Oh well, might just take a trip to Tennessee later this wk and visit Skip White.
     
  8. WALREC

    WALREC Registered Member Premium Member

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    ok,, stupid question... im still going out n back between gen 1 or LS. I almost went and got everything to build a 383 but all my buddys are pounding LS into my head, so im leaning LS but still on the fence.. anyway to my question,, ive noticed in pics of the LSs ive been looking at that has 4wd trans with it that the transfer case is a driver side drop. As far as front diff is concerned, is it really as simple as getting a diff w a driver drop instead of the K5s original (or any early gm) pass drop diff, or is there something im not seeing or taking into account. I know the drive shaft will need to be custom, im more concerned with geometry or compatibility of all working together properly (K5 frame n suspension, new driver drop transfer case, driver drop diff).

    it seems obvious to me that it don't matter what side of the engine the frt driveline is on, it should work as long as all parts are designed for that side but ive missed the obvious before.
     
  9. Wes Harden

    Wes Harden 1/2 ton status Premium Member

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    A lot of peps keeping Dr side drop are using Ford super duty front axles, d60, reverse rotation.

    Depending on the trans you can mate them to driver side drops. It all costs $$ you need to decide where ya spend it.

    I am a gen 1 guy too, the first ls I do will probably be my brother's 55 Chevy wide window.
    I like the 383 idea, it keeps popping up in my head.
     
  10. RoccoK5

    RoccoK5 1/2 ton status Premium Member

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    The 8L90 should bolt right up to a 32 spline NP241 passenger drop t-case. I'm sure there are adapters out there for 205 as well.
     

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