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383 Stroker Question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by raptordriver, Sep 5, 2000.

  1. raptordriver

    raptordriver Registered Member

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    Does anyone know a location where I can get a LOT of information on converting a 350 to a 383? As I understand it you stand to gain torque, move the torque curve down into the lower rpm's and do this without really losing much/any efficiency (gas mileage). A motor runs most efficiently at it's peak torque so this in theory makes sense.

    What I'm really wonding is how a the fuel injection setup would cope with the extra displacement. Would it need larger injectors? New computer? Is it just a dumb idea in the first place? Anyone have any good knowledge in this area?

    I'm pushing 120k miles right now and it's starting to blow some smoke but only on start up. It's definately got some life in it and still get's around 13mpg. But...I forsee a rebuild within a year or two and would like to start buying the part ahead of time so I'm only paying for machine work when the deed needs to be done.

    Thanks in advance,
    Larry Needham
     
  2. TexasK5er

    TexasK5er Registered Member

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    Moving to the top...I would like the same information...

    Nail It!!!!
     
  3. realsquash

    realsquash 1/2 ton status

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    If you check out just about all the car mags, there is an article about every month or so on how to build a "killer 383". New crank and rods, clearance a 350 block, slap on vortech heads the al. model of your choice, and call it done. You will need custom programming (Howell, etc) to make the ECM work right with the TBI, and it is very doable.

    Squash
    http://www.trailrunners4x4.org/users/realsquash
     
  4. Blazer79

    Blazer79 1/2 ton status

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    It's not a dumb idea. I think it's a great idea and has been done before. If you are currently using a TPI in your 350, you won't need to change injectors when going to a 383. These change is needed only if you're upgrading your TPI from a 305. You can get stroker kits at http://www.speedomotive.com

    http://www.summitracing also has a deluxe stroker kit but is about $1100.

    <font color=blue>//////
    http://blazer79.coloradok5.com
    </font color=blue>[​IMG]
     
  5. Brian 89KBlazer

    Brian 89KBlazer 1/2 ton status

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    I spent alot of time asking the same questions when the board was in it's early days and didn't get a lot of definitive answers (no offense to anyone who did offer help). I talked to Turbo City who recommended a modified TBI unit and an adjustable fuel pressure regulator. Others like Howell suggested the throttle body and a chip. Still others suggested the aforementioned and a fuel pump as well. I think the best advice I got was from a GMGoodwrench rep who told me to try the 383 with the stock setup and see how it goes. Then, only buy what I need to get it to work. I can't speak from experience yet but I think (HOPE!! [​IMG]) that throughout this winter, my TBI 350 will rebuilt to a TBI 383. If you can wait that long, I should have some definite answers to share. Otherwise, good luck and let us know how you make out! [​IMG]

    Brian
    89KBlazer
     
  6. keith

    keith 1/2 ton status

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    I'm doing this very thing in 3 weeks. I am getting a complete kit and new everything. The motor is going to put out around 400hp and 425tq. I can't wait to feel the difference
     
  7. realsquash

    realsquash 1/2 ton status

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    The GM guy gave u good advice. Just try the stock parts first and see what happens. BUT, if your cam is much hotter than stock, you really need to do a chip or have one done to get it to run perfectly. New FPR, larger TB, more ignition timing, etc are all band-aids in most cases.

    Squash
    http://www.trailrunners4x4.org/users/realsquash
     
  8. Brian 89KBlazer

    Brian 89KBlazer 1/2 ton status

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    Thanks squash; thats one important point I forgot to make. TBI computers don't take kindly to big,lumpy cams; even a custom chip can have trouble if the cam is too radical. Keep it to a computer friendly cam like the Crane Compucams. I've got a couple of model numbers if you need or want them.

    Brian
    89KBlazer
     
  9. Some one also makes an adjustable map,it compinsates for loss in vacume.I'll try to find it later and post the info.
    If you use a small cam like a crane 2032 compu cam you'll probably be ok.It should run ok if you stay small with the cam,but you wont get its full potental with the stock chip
    and throtle body.My friend has a 88 truck with a 383,it has
    dart s/r heads and a small comp cam,he also bought a holley
    performance replacement throttle body and edlebrock intake.
    It dynoed at 318 hp,412 lbs torque.He had a chip burnt though.The best thing to do is burn the chip on the dyno,you can do it on the road its just alittle harder to get it right.Hope this helps.


    IF IT AINT BIG IT AINT BAD!!!!!!
     
  10. realsquash

    realsquash 1/2 ton status

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  11. realsquash

    realsquash 1/2 ton status

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    Yeah, if you don't want to spend the time doing it yourself, you should really do like your friend and pay to have it done on a dyno ($$$$). I'm taking my truck to the rear-wheel dyno in about 1.5 weeks for final tuning. The hardest part of tuning a GM EFI system is to get the drivability set up correctly. But once it is, watch out!

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

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