1980 z basics

Discussion in 'Engine Topic' started by balloonpilot, Dec 18, 2020.

  1. balloonpilot

    balloonpilot New Member

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    I recently bought a 1980 z 350 4speed as a project for my son and I.
    The previous owner did not appear to know much about what he was doing.
    Most if not all of the emissions have been removed. It runs, but is rough.
    Can anyone give me or draw me a diagram of what is the minimum needed to run this car?
    Thanks.
     
  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    There isn’t much “needed” for emissions for the car to run.

    Do you need emissions testing to get it licensed where you live?

    Disconnected vacuum lines (and vacuum leaks) can be a problem.

    Carb settings, valve adjustment, distributor timing, plugs and wires are also things to check out.

    To say it “runs rough” doesn’t give us much of a description to help diagnose problems.
     
  3. COPO

    COPO Veteran Member Lifetime Gold Member

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    My 80 Z28 4 speed I ordered new and sold in 1990. I didn’t remove anything. Norwood car.
    DC01E732-76DD-437B-A5AF-E579F04A6923.jpeg
     
  4. cadillac_al

    cadillac_al Veteran Member

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    All you "need" is 12 volts to the distributor and a distributor vacuum line to the carb and the PCV valve hooked to the carb. Then you can fiddle with the timing and idle mixture to get it running smooth.
     
  5. balloonpilot

    balloonpilot New Member

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    I rebuilt the carb (holly) and adjusted it to the instructions with the rebuild kit.
    It will start and idle well but hesitates and bogs down when giving it any gas beyond idle.
    I played with the timing some, but didn't see any improvements.
    Couldn't see the timing marks at the time and am working on making them more visible right now.
    My next move was to start checking the vacuum lines that are there to look for leaks (they are hard and I figured that they are brittle too) but before I start replacing them, I want to know what I need and what I do not.
    There is no emissions testing on a car this age in my state.
     
  6. Chevyforever

    Chevyforever Veteran Member

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    Is your fuel pump working 100 % ? Cheap part that can cause symptom you mention.
     
  7. COPO

    COPO Veteran Member Lifetime Gold Member

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    No wonder. You bought a Holly. Buy the real one, a Holley. Kidding aside I’d get a Quad back on it like it came from the factory.
     
    brooksman9 likes this.
  8. GoldenOne7710

    GoldenOne7710 Equal Opportunity Offender Lifetime Gold Member

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    I'd say 1st and foremost, make sure your ignition is sound....and timing is correct. You cannot tune a carburetor (correctly) if the timing is wrong. Do you have a timing light?

    Like previously mentioned, you'll need to trace every vacuum line you see to make sure it's not open or broken.
     
  9. biker

    biker Veteran Member

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    And on the same theme, make sure your plugs, plug wires, dist cap and rotor are all good. A high mileage distributor may idle fine but as soon as the vacuum advance or mechanical advance can't move the way they should, it will run like poop.
    There is also a vacuum port above the throttle blades that isnt exposed to vacuum at idle. Once you move the throttle, that port "sees" vacuum, and if something connected to it is leaking, it will run poopy as well.
     
  10. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

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    ^^^including pulling the cap off and making sure the advance weights move freely and there isnt a rust issue.


    not sure what tuning you did to that holley. but it might need more tuning.
     
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