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Thanks for the replys & Clearification

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by det45, Aug 9, 2000.

  1. det45

    det45 1/2 ton status

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    Thanks for all of your replys from an earlier fourm. I got a lot of good info and I'm sure I will be able to use it in my future project. What I want to clearify is the two options I am entertaining as far as engine selections. My 89 is equipped with the 5.7 TBI and I want to increase torque and horse power. I have two ways to accomplish this; I could beef up the existing 5.7 via heads, electronics, etc. The other option is to replace the 5.7 with the carbureted 383 cid GM crate engine rated at 355hp @ 419lbs of torque. I know fuel injection has it's advantages but there are limitations on upgrades if one is NOT rich, (If you know what I mean) Anyway If I can effectively beef up the 5.7 TBI to the 383 hp/torque without going into the poor house, that's the way I want to go. If I go the 5.7 TBI direction, I will be pulling the engine and completely rebuilding it. The big question is? carbureted 383 or the upgraded TBI 350.Thanks you all.......Det45 P.S. You all are WAY WAY WAY WAY COOL !
     
  2. MudFrog

    MudFrog 1/2 ton status

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    Why not do the 383 and use the TBI? Just buy a chip that will increase the flow of the fuel to acomadate the engine.

    89 K5 Silverado
    http://mudfrog.coloradok5.com
     
  3. Kelboski

    Kelboski 1/2 ton status

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    nice problem......i would like to trade my 305 for a beefed up 350 one day.....Kelboski...are'nt these guys the best
     
  4. Blue85

    Blue85 Troll Premium Member

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    What gets the 383 to 355hp/419torque? If you are doing an engine rebuild anyway you could probably recreate it. You could bore and re-crank your 350 into a 383, buy some good heads, keep your TBI and get a new chip to compensate for the new engine displacement. This should be cheaper than the crate motor, which I believe is like $3000, and you would still have fuel injection. The only real expensive thing would be the heads, which are probably $1000. I have heard of guys reworking their heads with bigger valves and increased size runners, but I don't know if this is effective or worth the time/money. You probably also want to look into mass fuel flow and see about bigger injectors. Either way, you'll want to do something about your exhaust and air intake to actually get the rated power. I have never done this conversion, but if you can find the right chip, there's no reason why it shouldn't work. Your existing throttle body may be a bit restrictive, though.

    '85 JIMMY
    '90 paint/grill/trim 5"susp 33/12.5/16.5
    Fresh 350 B&M '87 TH700
     
  5. Emmettology 101

    Emmettology 101 3/4 ton status

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    Ya, I say keep you engine and make it a 383 w/TBI. Those numbers for the other 383 are lower than what I am used ot seeing, well at least for the HP.

    I have usually seen about 450HP and about 450 TQ....

    Is this just a lower HP version like a 300hp crate motor vs. a 350hp crate motor?



    Mike [​IMG]
    1982 GMC Jimmy - <font color=green>Emmett</font color=green>
    http://emmett.coloradok5.com
     
  6. realsquash

    realsquash 1/2 ton status

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    I'd go 383 or 350 w/vortec heads, 9:1 compression, 210/220 duration cam. And a good set of headers such as thorley headers. This engine will snort like hell and places like howell will make you a chip that will run your TBI well enough to make u happy. The only other possible EFI upgrade you might make is a larger TBI from a 454 or one that has been hogged out from turbocity, etc.

    You don't have to be rich to keep the EFI you already have and make it work.

    Squash
    http://www.trailrunners4x4.org/users/realsquash
     
  7. det45

    det45 1/2 ton status

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    Once again thanks for your replys. So you all think I can make my existing 5.7 TBI into a 383 and utilize the existing TBI with an upgraded chip? From what I understand as far as converting the 5.7 to a 383, all I need to do is to replace the 350 crank for a 400 crank. Also I will need to get a new harmonic balancer/ flexplate and have the assembly balanced. Now as far as the TBI is concerned, should I use the stock set up on the 383 conversion with a new chip or will I need to change the heads and intake along with the chip? Does anyone know if the stock heads on the TBI 5.7 flow well for a 383 conversion? Sorry for all of the questions but I'm trying to get the most bang for the buck without going broke. You all are the best! Thanks......Det45
     
  8. Blazer79

    Blazer79 1/2 ton status

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    Well, some heads can cost the $1000 you said or even more, but the $3000 Crate engine comes with $400 Vortec Heads [​IMG].

    I have a 350 and someday I'll rebuild it with the 383 crank and get the Vortec Heads. If for example you get Summit's stroker kit ($1,100) and the Vortec heads, you'll have the new engine for $1,500. Just add the block prep and assembly costs. I've seen stroker kits (pistons, crankshaft, etc.) for about $650 on the internet, so you could lower your costs if you find one like that.

    <font color=blue>//////
    http://blazer79.coloradok5.com
    </font color=blue>[​IMG]
     

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