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350 TBI to 454 TBI?

Discussion in 'The Garage' started by Shagnaz, Oct 8, 2003.

  1. Shagnaz

    Shagnaz 1/2 ton status

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    Has anyone done this. I have a 1990 K5 with the TBI setup and want to drop in a 454 with it's TBI setup. Do I need to change anything out with the injection system?

    Thanks
    /forums/images/graemlins/thumb.gif
     
  2. fortcollinsram

    fortcollinsram 1/2 ton status

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    I have a 1987 K5 that I swapped in a 1992 454TBI...It was pretty damn simple...The ECM pinout is the same between the 7747 and 8747 ECM's the thing you need to watch for is if you get a 454 engine that had a 4l80E tranny, then the wiring harness WILL be different...Stick with a 454TBI that has the 8747 ECM that had a TH400 or a manual tranny and you will be good...

    The 454 had a FEW differences in the wiring harness, most noteable the EGR solinoid and oil pressure swith...The OP swith on the 1992 has the switch and sender on the same dealie, but my 1987 had 2 (one for the gauge and one for the ECM) I simply add the one for the gauge...It was pretty simple wiring acually...

    You DO need the 454 TBI and the 454 Injectors. It was a pretty easy swap..ONce I had the motor in my truck t was running in a matter of days, I just had to lengthen some of the wires since the 454 is so much bigger and b/c mine has a serp. belt instead of V's so I had to accomodate the alt. being on the opposite siade that it was...

    all it in all, it is VERY worth it...

    Chris
     
  3. Shagnaz

    Shagnaz 1/2 ton status

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    I have a TBI set up now on my SBC. Do I have to
    use the wiring for the 454? I was thinking I could
    just unhook the SB, add the 454 TBI unit to the motor, and then hook everything back up using the same ecm or get the
    454 ecm which should be the same plug. I might be wrong.
    Just thought that since a nice upgrade was to go from the orginal TBI to the 454 TBI unit on the SB.
     
  4. fortcollinsram

    fortcollinsram 1/2 ton status

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    OHHHHH... I SEE... YOU JUST WANNA swap the throttle body...Yeah you can reuse your wiring...I had to "modify" a bit of the wiring harness b/c the sensors plug-ins on the 1992 454 TB were different than the sensors on my 87 SBC TBI...It was simple though...You WILL need to use you 350 ECM...and you will need the stock 350 injectors..the 454 injectors are WAY too big for a 350...

    You will need:

    -454 throttle body and sensors (you just need the TB, not the injector pod/ FPR assembly, since the 350 injector pod will bolt to the 454 TB)
    -Maybe a few wiring connectors to splice new connectors (for the new TB) into you old harness

    Chris
     
  5. Shagnaz

    Shagnaz 1/2 ton status

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    Well, you got some of my question. I am taking out my
    TBI 350 and installing a TBI 454.
    I know that the accessories will be in different spots.
    Just thought they would be set up the same, just one's bigger than the other.

    Thanks
    Mike B
     

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