Manual trans numbered q jet on auto 455

Discussion in 'The Venerable Q-Jet' started by Speedfreak, Dec 17, 2017.

  1. Speedfreak

    Speedfreak Member

    I have a 72 centurion with the w engine code which is supposedly a bit higher performance than the standard 455
    Anyhow it's a lower mileage car appearing unmolested
    The carb was acting a bit lean so I figured it's old I'll go through it
    Turns out upon pulling it the bolts were a bit loose but I'm here so onward
    I pull it to see a number 7042243 mb
    Seems to denote 455 manual trans application 1972
    Carb looked to have come on it
    Just wondering if I should be worried about metering differences possibly
    Car pulled hard so.....
     
  2. hugger

    hugger Well-Known Member

    I would sell that carb , get a fresh "1540" that carb is a RARE one, not many 455 4speeds in 72

    One of the builders may even just take it in exchange for a fresh one,...i would
     
  3. NZ GS 400

    NZ GS 400 Gold Level Contributor

    I agree with hugger.
     
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  4. techg8

    techg8 The BS GS

    No worries using that carb in place of the 2240 auto carb.

    Although the others are right it's a rare carb.
     
  5. Speedfreak

    Speedfreak Member

    I appreciate the responses
    The whole car is kind of an odd ball
    Only options that matter are ac and amfm stereo besides the w code 455
    It moves fairly well believe it or not
    Can't wait to get the carb back on this evening
    Thanks again!
     
  6. tdacton

    tdacton Gold Level Contributor

    Attached Files:

  7. Speedfreak

    Speedfreak Member

    I just went through it I'll post a pic of the code
     
  8. STAGE III

    STAGE III Lost Experimental 455-4 Bolt Main Block.

    IMG_3144.JPG IMG_3145.JPG IMG_3146.JPG IMG_3147.JPG While Speedfreak is doing his teardown is my barn find a genuine 72 Stage a roonie Auto?
     
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  9. hugger

    hugger Well-Known Member

  10. STAGE III

    STAGE III Lost Experimental 455-4 Bolt Main Block.

    Thanks Ethan I thought this was stolen from me back in the 1980's so glad I NOW know the guy got my 1970 Hi-Compression 350 carb instead:D:D:D:D:D:D !!! LOSER LOST!!!
     
  11. STAGE III

    STAGE III Lost Experimental 455-4 Bolt Main Block.

    Now back to the ultra rare 4 speed carb! Cool story Speedfreak!
     
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  12. carmantx

    carmantx Never Surrender

    The jets and primary rods are same on the 2240 or 2243. There would be tiny differences.
    The 2242 has some different Jets/rods!
     
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  13. STAGE III

    STAGE III Lost Experimental 455-4 Bolt Main Block.

    Is that good or bad for mine, Mark? I am rare carb challenged :D
    Found my air pump and all in the same crate. Glad I throw NOTHING away lol
     
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  14. carmantx

    carmantx Never Surrender

    The Stage 1 carbs were calibrated a bit different John so they would be matched for the engine. Jets 2 steps larger and primary rods 1 step smaller on the 72.
     
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  15. STAGE III

    STAGE III Lost Experimental 455-4 Bolt Main Block.

    Thanks, Mark.
    okay I better chill and let SpeedFreak get back to his thread, thanks for info & sorry for interruption SpeedFreak
     
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  16. 87GN_70GS

    87GN_70GS Well-Known Member

    Yes, 4 speed. Notice the POE holes below the flaps
     
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  17. NZ GS 400

    NZ GS 400 Gold Level Contributor

    Scott,
    What are POE holes? Thanks.
     
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  18. Cliff R

    Cliff R Well-Known Member

    POE stands for Pull Over Enrichment. It is a system used on most Q-jets on the secondary side to add some fuel when the huge secondaries come on line and it will continue to add fuel until the wells that the supply tubes are in go empty. It acts like a secondary side accl pump system. Since the system is activated by pressure differential (no pump is used) moving the holes under the flaps gets it going sooner and directs the fuel under the flaps directly into the intake.

    There were several attempts by Rochester to employ secondary POE in manners that gave it a direct shot to the engine. Early Pontiac Q-jets used "slotted" secondary air flaps, later models located a larger exit hole directly in line with the flaps so fuel could come out under them.

    Many Qjets also used primary side POE so they could run a very lean mixture and it was very quickly supplemented if/when needed by quick/heavy throttle openings. When you see 6 tubes hanging from the airhorn the primary side POE is present. Early Pontiac carbs from 1969 and 1970 also used primary side POE (non Ram Air units) which located the tubes inside the main secondary fuel passages with exit on the primary side behind the choke flap. Primary side POE disappeared for the most part in the late 1970's when they went to the single main airbleed designs since they are more precise for fuel delivery across the load/speed range......Cliff
     
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  19. DBS

    DBS Well-Known Member

    From the QJ master guru. Thanks. Currently reading your book.
     
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  20. Speedfreak

    Speedfreak Member

    That's a wealth of information !
    So.......I cleaned my carb. The erroneous 3 cleaned up to read 0
    So I guess it's good and bad
    No I don't have a rare q jet but I do have the original one lol
     

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