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350 vs 454 tbi

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by muddysub, Dec 10, 2001.

  1. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    i have a tbi 350 and i was wondering if it would be good to swap out my tbi for one off of a 454. would there be a mileage drop or gain? would i really get any more power out of it? i've seen adapter plates for it (454 tbi on a 350 manifold ) and was just wondering.

    people that get good mileage aren't having any fun!
    scott,
    1989 GMC suburban 3/4t 4" lift finally rollin on 36" swampers, tbi350, th350, np241
     
  2. greg83k5

    greg83k5 1/2 ton status

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    i'd assume the output at a given pulsewidth duration ( is that redundant?) of the 454 tbi would not match up with what your 350 computer was trying to accomplish, there being a decent difference in lb/hr ratings for the two injector assemblies..... so you'd run rich as crap, 'cause your ecm would think it's driving the normal injectors....

    however, this may be an interesting avenue to pursue for the stroker folks who could get a custom chip and are at the limits of what their 350 tbi's are capable of flowing..... blahbity blah....

    ( this is just me thinking out loud, maybe a more enlightened soul will come through and shed some better light...)

    greg

    ** i'm so money **
     
  3. 425 Xpedition

    425 Xpedition 1/2 ton status

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    The 454tbi has a higher cfm and bigger injectors. Unless you have some good engines mods, putting it on will hurt performance.

    1990 Crew Cab, 14" lift , 39 x 18 Mickeys, 16.5 x 14 Welds, Dana 60 & 14 bolt, Traclock & Detroit Locker, 4.56gears, 454TBI, Turbo 400, 205
     
  4. Thunder

    Thunder 3/4 ton status

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    You would need a reprogramed PROM chip.
    The 454 TBI also has a different IAC valve that you have to get an adapter for.
    If you want more flow without a bunch of computer mods check out:<a target="_blank" href=http://www.turbocity.com/TBIPowerMain.htm>Turbocity.com</a>
    The high flow TBI, Matched injectors, and adjustable fuel pressure regulator would be a good start.
     
  5. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    well nevermind then, i just thought i'd ask, thanks for setting me straight.

    people that get good mileage aren't having any fun!
    scott,
    1989 GMC suburban 3/4t 4" lift finally rollin on 36" swampers, tbi350, th350, np241
     

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