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Thread: 1994 sierra...stock tbi to Atomic conversion

  1. #1

    Default 1994 sierra...stock tbi to Atomic conversion

    Im so sick of dealing with my stock tbi setup on my 1994 sierra! I have tried so many upgrades, tips, and tricks, but i still can not get the performance i want out of it. Plus, i'm very limited to my tuning option since everything is controlled by the PROM. I want to know if anyone has converted a vehicle like mine to the Atomic kit? Would i see better performance? Fuel mileage? What would i need to do to run this setup on my truck? I know i need a carb intake and a HEI dist.

  2. #2

    Default 1994 sierra...stock tbi to Atomic conversion

    And would i be able to run the 4l60E trans with the Atomic Kit?

  3. #3

    Default 1994 sierra...stock tbi to Atomic conversion

    And would i be able to run the 4l60E trans with the Atomic Kit?

  4. #4

    Default 1994 sierra...stock tbi to Atomic conversion

    I don't believe you would see better mileage only because a factory setup runs very lean as it is so a proper tune that adds a bit of fuel for better throttle response would net a bit less not more.

    I have not done this conversion but it can be done. Besides your intake and dizzy you would need a trans controller to support your electronic trans. There may be other computer controlled devices that would also fail to operate but I can't think of any offhand.

  5. #5
    msdtech1955 Guest

    Default 1994 sierra...stock tbi to Atomic conversion

    actually, it can be done..."BUT" ..

    1) you will need a controller for the transmission( street rodder guys would know)

    2) we need to see about the emission laws in your state ( to see if that can be done)

    3) would need new intake and a 85551 or 85501 distributor ( to trigger the msd box)

    4) also: a 84211 adjustable rotor ( to fine tune rotor phasing)

    5)cruise control mount might have to be modified to fit.( depends on the intake you get)

    ( alot of investment)

    you may want to check with howell engineering or maybe street and performance


  6. #6

    Default 1994 sierra...stock tbi to Atomic conversion

    Well all that is some good info... This is more of a long term outlook on the destination i have in mind for this project. Money isnt really that big of a deal as long as it is spent on good quality reliable, and good performing parts. I just really like the simplicty of the atomic. I think my first move is actually going to be to strip out all the stock computer stuff and do true carb conversion on it. That wont be very expensive. Then I can later go through and hook up the atomic system and it would be just like setting it up on a carbed vehicle

  7. #7
    Join Date
    Oct 2018
    Sonoma ca


    Make sure all your tbi parts are good. Check shaft play for the throttle blades. Make sure your o2 sensor is new. Get it running great. After that try a 454 throttle body with 350 injectors. The 454 injectors are too big.

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