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Engine replacement??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Frogg89, Jan 27, 2004.

  1. Frogg89

    Frogg89 Registered Member

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    Im thinking about replacing my block and heads since I have a head gasket leak and the engine is real tired anyway(149,000k). Does anyone know if I would have a lot of problems with my tbi and computer type crap if I decided to get some more power like a 350 that has around 350hp??? Would I have to go with a carb and probably lose my actually good emmissions(state inspection)? /forums/images/graemlins/k5.gif
     
  2. Topdown

    Topdown 1/2 ton status

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    Someone correct me if I am wrong, but you shouldnt have any issues with a higher-output engine and a stock TBI. At some point you will need to put bigger jets (injectors?) in it but with a mild build like 350hp you should be ok.
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Are you the original owner? You'd be surprised how much more powerful even a stock rebuild feels after replacing yours. The engine block and heads is just part of the equation. You will have to use intake/exhaust/chip mods together to see that much horsepower. If you installed an engine that claimed 350 hp to get it youd have to duplicate the setup the dynoed it with! Also dont ditch your injection, I'd love it myself for two reasons idle quality and off camber performance. Hope this helped. /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif
    Paul
     
  4. Topdown

    Topdown 1/2 ton status

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    If your really looking for an "upgrade" to your motor, I have a 410hp 425ft-lb (yes it was dyno'd, with a 650CFM carb) small block 350 sitting on my garage floor that I have been trying to sell. Its carbed, but all that can be replaced with your stock TBI. /forums/images/graemlins/thumb.gif
     
  5. Frogg89

    Frogg89 Registered Member

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    Im not the original owner but the damn thing is so sluggish since I lifted it!! Its like driving a dump truck!! I just want to take advantage of the situation since I would have to pull the whole motor apart anyway!! /forums/images/graemlins/k5.gif
     
  6. 87BrnRsd

    87BrnRsd 1/2 ton status

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    I think I would buy that 410/425 engine that topdown is selling. That should make your blazer feel a little less like a dump truck.
    -Harrison
     
  7. Thunder

    Thunder 3/4 ton status

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    You will never get 350 hp out of stock 350 Tbi. The stock one on 350s is only good for around 280. it only flows 480-500 CFM. It runs out of air long before it makes 350 hp. You can get a 454 TB and go with Vortec heads/GMPP manifold and a performance cam and maby get up to around 340 hp with a custom chip. If the chip is done right you should still be able to meet emissions.
     
  8. K1Orion

    K1Orion 1/2 ton status

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    off topic, Did your lift include taller tires? Your dumptruck like performance could be lack of gear, not engine giving up.

    I say buy a GM crate motor and keep your TBI. Or buy topdown's dynoed motor. /forums/images/graemlins/waytogo.gif
     
  9. Frogg89

    Frogg89 Registered Member

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    Yeah I have 36s, but I also swapped to 4:56s also!!! /forums/images/graemlins/k5.gif
     
  10. Frogg89

    Frogg89 Registered Member

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    [ QUOTE ]
    You will never get 350 hp out of stock 350 Tbi. The stock one on 350s is only good for around 280. it only flows 480-500 CFM.

    [/ QUOTE ] Cant I replace the injecters to help with the added HP????
     
  11. Thunder

    Thunder 3/4 ton status

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    It depends on what you want to do with the engine.
    If you keep the stock intake and heads there is no need to get bigger injectors they just dont flow well enough to support them. All you really need is an adjustable fuel pressure regulator.

    If you build the engine with better flowing heads like World torquer II or Vortecs,aftermarket intake manifold, cam, higher comp ratio then you could step up to 65 lb hr injectors and an adjustable FP regulator to fine tune it.

    Rather than me do a whole bunch of typing go here: cfm-tech.com
    Click on all the links on the left side of the page and spend some time reading the tech articles. They will help you understand TBI and what you can and cant do to it and why.
    They also sell many parts you need to build your TBI to make the higher HP you are after.

    http://www.turbocity.com also sells TBI upgrade parts
    I have delt with both these people. Both are pretty good with TBI and can help you with the parts you need and offer tech help.
    If you are going to do a performance build I highly recomend you get a good scanner like AutoXray. It will help in chasing down problems and when trying to fine tune things.
    Hope this helps.
     
  12. 84mudmachine

    84mudmachine 1/2 ton status

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    Stay away from GM crate motors. I have a 350 with a 3yr/50,000 mile waranty that came up with a cracked head, and Gm doesn't want to take care of it since it was installed by an individual. Come to find out the motors are cast in Mexico, and the heads are done thinner than they should be. Just thought I would warn you.........
     

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