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TBI Swap Info Needed (350 > 454)

Discussion in 'The Garage' started by nvrenuf, Sep 29, 2005.

  1. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Ok, I know this subject has been beat to death but...

    For the TBI, what all do I need to convert my 91 crew cab from a 350 to 454?

    I have purchased a 454 throttle body with manifold (unknown year), seems like I read that I only need to change the TPS and IAC connectors - is that correct? Is there a good source for new connectors? I'm fairly certain these parts came from a C/K truck, will that matter? Any good online sources or books for "decoding" the throttle body application by part number (like a carb)?

    After all of that, do I need to change the PROM?

    TIA!!!
     
  2. bad_bo_ti

    bad_bo_ti 1/2 ton status

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    i maby be wrong but i am thinking the comoputer or chip needs changed also for the 454, you can only run so big over the stock chip before you need another one. but if it is a modified big block might as well get one burnt for it. hope this helps as far as the two sensors just go to a junk yard and hack them off a big block if needed then take them home and repin it in the harness. chris
     
  3. Russ

    Russ 1/2 ton status

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    John,
    I am in the middle of doing this right now. I have a 454 and 350 harness and will compare the two and let you know exactly what is different. Yours will probably be more complicated than mine since your truck is newer, so I believe your 350 harness is set up differently. I know there are only a couple of connectors that are different, but a few of the components are in different places.

    Russ
     
  4. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    I have no idea on the other stuff, but as I recall, you don't even need the manifold since the 454 TBI uses an adapter to mount on a q-jet manifold. No need to waste money on shipping that anchor, and maybe upgrade to an aluminum dual plane...
     
  5. tarussell

    tarussell 1/2 ton status

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  6. Thunder

    Thunder 3/4 ton status

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    350 and 454 are pretty much the same except for things noted in these posts. IAC TPS Chip ect. what conectors you need may also depend on the year of the engine and wireing harness
    http://www.turbocity.com has adapters that plug 454 into 350 wireing harness. give them a call or email. They can help you out.
     

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