Which carburetor should i choose???

Discussion in 'Engine Topic' started by jemeah, Aug 18, 2009.

  1. jemeah

    jemeah New Member

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    Hi from Turkey,i have a stock 74 Firebird Formula 400..only got edelbrock performer series manifold and 500 cfm edelbrock carburetor..but i have a problem,when i step on the gas there is a black exhaust smoke.. why??everybody says that it should be carburetor not fit my spec. i should to buy 600 cfm..is it correct?if correct which brand i should choose ?rebuild q jet?600 edelbrock?or holley??
    :rolleyes:
     
  2. MrZeal

    MrZeal Member

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    Do they really have a drag strip in Istanbul? What are the rest of the specs on your motor?
     
  3. jemeah

    jemeah New Member

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    i have stock 400 block,4x heads,stock camshaft,edelbrock performer manifold..
     
  4. docwilcar

    docwilcar Veteran Member

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    If you are getting black smoke then it is running too rich. Unless someone put some rich rods and jets in it then I would bet the floats are set too high or your needle and seats are allowing too much fuel into the carb due to some crud. 500 cfm should be enough for a stock 400 up to about 4900. A stock 65 GTO had an AFB with about 550 cfm rating. There is really no difference between a 500 and 600 Edel. except for the jets and rods that they install at the factory. Also check that you are not getting more than 6 psi from your fuel pump. Stock rods on a 500 Edel. are .065X.052 and jets are primary-.086, secondary-.095 To update to 600 specs use .070X.047 rods, .100 primary jets and .095 secondary jets. Your float height should be 7/16" and float drop around 1-1 1/4".
     
    Last edited: Aug 19, 2009
  5. MrZeal

    MrZeal Member

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    600 Holley
     
  6. jemeah

    jemeah New Member

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    I see..But what can i do in this case? Changing my carb? or buying maintenance Kits to fix it??
     
  7. pdq67

    pdq67 BANNED

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    Try to hunt up a stock 750 Q-Jet and go.

    Just set the top back air-valve butterfly's to kick in at the rpm that you want them to.

    pdq67
     
  8. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    I was running a 750 manual choke edelbrock right out of the box, on a 10:1 compression pontiac 400, automatic, and it ran great (as great as a pontiac can run I suppose)

    A 500 edelbrock is way too small
     
  9. Chevynut67

    Chevynut67 Veteran Member

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    Jemeah,

    Do you know Burak Sozer?

    He's a good friend of mine, maybe he can help you find a qjet.
     
  10. jemeah

    jemeah New Member

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    Yeah i found his facebook profile and sent a message to him ;)

    So everybody like minded about 750cfm.. but its hard to find good condition q.jet in here..

    how is remanufactured q.jets in summit??
     

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