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vacuum lines

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by lasvegas, Nov 17, 2001.

  1. lasvegas

    lasvegas 1/2 ton status

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    Almost done putting in the ZZ4. I bought a Quadrajet from Jet. Trying to figure out what to do with two vacuum lines. Does anyone know where I am supposed to hook up the vacuum advance on the distributor and also the vacuum line on the brake system (I think this goes to the manifold?). Also, is a PCV necessary? If so, where do I hook that up? And last, can anyone tell me what all the vacuum hookups are on the carb or is there somewhere I can look. Jet was ZERO help and told me to go look in a manual - but what sort of customer support could I expect for $400.00?
     
  2. mike reeh

    mike reeh 1/2 ton status

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    stock, my distributor is on ported vacuum.. most people especially with far-from-stock setups play with different setups and see which they like best.. it depends a lot on what your initial & total timing is set to.

    Brake booster usually connects to the big port on the back of the Q, on the baseplate.. on my truck, there is a metal tube that comes out a few inches, bends around to a bracket then from there the rubber line to the booster.

    you should definately run pcv..that hooks up to bigger of the ports on the front of the carb, on the baseplate again... I think its like 5/16" or so. As for the other ports, most of them are ported vacuum.. you can blow compressed air thru them and listen where it comes out.. if it comes out right at the throttle butterflies, or above, then its ported.. if it goes sraight to the manifold, its not ported. It would be good to get a vacuum gauge and connect it to each port and see how it responds at idle, slight throttle, etc.. make sure the ones that arent being used, are plugged obviously.

    you could get an o.k. idea of what each are by looking at a factory vacuum diagram..

    what year vehicle are we talking about?

    mike
     
  3. lasvegas

    lasvegas 1/2 ton status

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    Thanks for responding. It is a '78, but with the exception of the brake master cylinder, nothing else at all under the hood is stock. Does this lead to more thoughts?
     
  4. mike reeh

    mike reeh 1/2 ton status

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    no, thats good though because I was "generally speaking" about my truck which is a '77.. into the 80's im sure stuff changed.

    mike
     
  5. 1986Blazer

    1986Blazer 1/2 ton status

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    If you send me an email tomorrow and remind me...I will take digital pics of how the vac lines on my quad jet are set up. I will trace each one you asked for and show you how they mate up to the carb. My email is:

    spilikus@sprynet.com

    Chris

    <a target="_blank" href=http://www.geocities.com/keywestk5/KeyWestK5.html>http://www.geocities.com/keywestk5/KeyWestK5.html</a>
    So I says to him, I said, "get your own monkey."
    1986 K5, 350 GM Crate, 700R4, NP208
     

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