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Is 350-400 HP possible on high flow TBI! ?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by TEXICAN, May 1, 2006.

  1. TEXICAN

    TEXICAN Registered Member

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    Is any one pushing 350-400 Hp on TBI setup.

    My engine is at the machine shop! Im worried i wont be able to get my TBI setup properly. Right now my block is being bored .30 over, zero decked,9.5 compression, keith black pistons, scat i beam rods, these are the Isky cam specs the machinest gave me 2000-5000
    Int. .435 262 208 C.50
    Ext .445 270 216 112 lube center
    I plan on running headers, so far ive been recommended by XtremeFI to run there 50MM Hi flow Tbi, afpr, and injector spacer. Im not sure what kind of HP i will be pushing ive been told 350-400. Im new to all this and dont have a clue im just wondering what TBI mods i would need to have a proper running engine.
    Any comments would be appreciated.
     
  2. HarryH3

    HarryH3 1 ton status Author

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    I think you need to be chatting with the tech support folks at someplace like www.turbocity.com The stock injectors are designed to supply enough fuel for a 200 HP engine. It would take some pretty insane fuel pressure to squeeze enough fuel through them to feed 350-400 HP. :yikes: I'm thinking you'll do better if you start with a 454 throttle body. It has bigger injectors and larger bores, so it's much more suited for bigger HP applications. You'll most likely have to have the intake bored out to the same diameter as the 454 bores.

    You're also gonna have to spend some cash on a new, custom tuned chip if you want to get the max performance from the new engine.
     
  3. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    Sure, with enough fuel pressure & volume, a big enough throttle body, and a ECM programmed to run it. Holley claims their biggest 900cfm 4V TBI system is good for up to about 500 HP. 275HP on their 670cfm 2V TBI setup.
     
  4. chevyk2500hd

    chevyk2500hd 1/2 ton status

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    First start with a bored 350 tbi. You can find them on ebay cheap. Then use 454 injectors. Then talk to Brian and http://www.tbichips.com. He got my 383 running great and I am pushing 330 or so. A 454 tbi wont work unless you get some custom intake for it i think. I just had my intake bored to match my bigger tbi.
     
  5. neverendingproject

    neverendingproject 1/2 ton status

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    The holley 670 will do the 350 HP no prob. My 383 will be putting about 340. The key is getting a new Holley TBI with the delphi injectors and crank up your pressure. the Holley TBI has an adjustable fuel pressure regulator, but I think you have to take the little cap off the top of the screw to do it, IIRC.

    Edit: I had also talked to the guy at TBICHIPS and he said that the Holley will work with the higher pressure. You just have to make sure you have the delphi injectors.
     

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