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Motor rebuild...... any comments

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by mrprex, Apr 14, 2000.

  1. mrprex

    mrprex Registered Member

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    This summer I plan on dropping the stock 350 out of my '88 and having it reworked. I am putting 1.94-1.60 heads on. speed pro 9:1 pistons will be going into .030 bored cylinders. Also I am going to stroke it out with a milled 400 crank and throw long rods into it to pump a little more torque into it. Here is the catch. I am trying to stay within the ballpark of emmisions (which is why I am not putting 2.02 heads on it) and I really want to put an aftermarket TBI on it. Something like the edelbrock performance TBI with the matched intake. The chip that comes with it will help the emission issue a little but I was told that putting a dual exhaust under the truck wouldn't be a great idea because of emissions. Why build the block if you can't let it breathe? There are a lot of knowledgable people on this site and if some of you put in your 2 cents about the effects of this rebuild on emissions it would be greatly appreciated. Thanks in advance.
     
  2. Blazer79

    Blazer79 1/2 ton status

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    I think that sounds like a nice setup you have there. The only reason a dual exhaust would affect your emissions is if you don't install dual cats. Also if your current exhast has an 02 sensor, make sure you keep it on the new exhaust. Just check your local laws to make sure what you can and can't do.

    If you want high flow cats, Summit has Catcos for $50. If you want the best flowing cats go with Random Technology, but they are about $250 each! [​IMG]

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     
  3. SVBlazer

    SVBlazer 1/2 ton status

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    There are several aftermarket CARB approved exhaust systems available. Edlebrock comes to mind. This system has all the air injection buses and o2 sensor mounts installed. Put this with a cat-back system and your legelly flying down the road. 'course none of this comes cheap...
     
  4. coopertwpk

    coopertwpk 1/2 ton status

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    actually your dual exhaust will kill your low end torque most torker motors run 2.5 out to a 3 or 3.5 cat back.
     
  5. mrprex

    mrprex Registered Member

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    I'll check into it. Besides you guys I have only talked to a couple of people, mostly drag motor heads. I think I might try a single plane manifold for the torque and either hooker headers or hi-flow headers. I'll keep you all posted as to what routes I have narrowed it down to and ask again later before I buy the hardware. It's just the thought of having 2.5 or s inch pipes growling behind the rear tires that gets my blood going. Thanks all.
     
  6. Blaze81

    Blaze81 Registered Member

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    If you are talking about a single plane "intake" manifiold the single planes are more for high RPM horsepower. The dual plane ones are designed more toward producing torque. A lot of articles that I have read and dyno comparisons say that you loose low end torque a little with single plane intakes. No experience personally just read a lot about because I was thinking the same thing. Went with a Weiand dual plane and like it very well. Hope this helps a little.

    Tuck
     
  7. rich

    rich 1/2 ton status

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    I agree - go with a dual plane intake for torque. A single plane intake is for high RPM horsepower.

    Also, a HUGE dual exhaust might hurt torque, but somewhere between 2" and 2.5" dual exhausts should be good for torque, especially with a larger engine like a 383, if your local emissions laws allow adding duals. And a crossover or "H" pipe between the two exhaust pipes, as close as possible to the headers, will help torque too, but make sure it won't hurt your ground clearance.

    Richard
    '76 K-5 Blazer
    '91 K-5 Blazer
     

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