Stage 1 vs non Stage 1 Quadrajet

Discussion in 'The Mixing shop.' started by rkammer, Sep 20, 2020.

  1. rkammer

    rkammer Silver Level contributor

    Can one of you folks familiar with the 1970 QJ list the things that are different between the Stage 1 QJ and the standard 455 QJ? Jets, metering rods, power valve springs float levels, air valve settings, whatever?

    And, how about the same questions on the '71 and up QJs?
     
  2. john.schaefer77

    john.schaefer77 Well-Known Member

    I'll check my book tomorrow but I know off the top of my head the '70 stage is jetted fatter than the non stage.
     
  3. john.schaefer77

    john.schaefer77 Well-Known Member

    I checked because you had me curious. The non stage has a float level of 3/8 and the stage has 5/16. The non stage jet is a 67 and the stage is a 68.

    Non stage metering rods are .041, stage. 042. Secondary rods are AY on the non stage and AU on the stage.

    The air valves on both state 1/2 turn.
    This is in the '70 Chassis manual page 64-36/37
     
    BadBrad likes this.
  4. techg8

    techg8 The BS GS

    Stage1 has secondary pullover enrichment holes below the air flaps, and non stage1 are above the flaps (excepting 4 spd carbs)
     
  5. telriv

    telriv Well-Known Member

    Don't know for sure but I also believe there might be differences in idle air bleeds & idle jet sizes.
     
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

  7. shiftbyear

    shiftbyear Well-Known Member

    Another difference is about $2000
     
    BYoung, Waterboy and GSST1 like this.
  8. Bigpig455

    Bigpig455 Fastest of the slow....

    with all I know about carbs, could somebody explain to me what a "spark hole" is?
     
  9. BadBrad

    BadBrad Got 4-speed?

    I'll speculate re: spark hole: Vacuum advance port. That being said you can run same above or below the butterfly.
     
  10. TimR

    TimR Nutcase at large

    I plan on going through my original 7041242 this winter. Started having a few issues late this summer after 20+ years of perfect running (I kid you not). One of the reasons is to get all the measurements/specs (idle tubes/air bleeds/apt etc) so a guy can duplicate it on the cheaper (say 7041540) carbs and run them, this thing has been a real champ. Only change from stock is 76 jets installed for lean miss with 288-94H cam back in 1997 (not ideal solution but it worked so don't even say it!LOL).
     

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