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Thread: 4776-600 cfm

  1. #1
    roudabush Guest

    Default 4776-600 cfm

    Can anyone offer suggestions on how to get the most out of this carb running on a dirt car.Engine is 360 ci chevy,11 to 1,race fuel,bow ties,262-268 cam,7000 rpm.Running 72-75 jets,power valve 4.5 front and back.Runs good now looking to make it better on restarts

  2. #2
    rickyr Guest

    Default

    About all you can do is get the power valve and jets right, and to do that
    For the power valve size you will need to
    check your engine vacuum @ idle ( in gear if auto trans )
    then cut your reading in 1/2 for a power valve size ( with a performance cam this needs to be done )

    After that is right
    all you can do is start with stock jets
    then run it @ part throttle for about 1/4 mile and kill the engine without letting it idle, and look at your spark plugs
    if they are white go up 2 jets sizes if black go down 2 sizes on the pri jets
    and check it again
    do this until they are tan to brown
    then do a wide open pass and kill the engine without letting it idle
    and jet the rear the same way
    After that if you have not allready you might want to remove the choke parts
    but do not mill the choke tower off that will make bad air across the air bleeds and can make problems
    Thanks

  3. #3
    roudabush Guest

    Smile

    Quote Originally Posted by rickyr View Post
    About all you can do is get the power valve and jets right, and to do that
    For the power valve size you will need to
    check your engine vacuum @ idle ( in gear if auto trans )
    then cut your reading in 1/2 for a power valve size ( with a performance cam this needs to be done )

    After that is right
    all you can do is start with stock jets
    then run it @ part throttle for about 1/4 mile and kill the engine without letting it idle, and look at your spark plugs
    if they are white go up 2 jets sizes if black go down 2 sizes on the pri jets
    and check it again
    do this until they are tan to brown
    then do a wide open pass and kill the engine without letting it idle
    and jet the rear the same way
    After that if you have not allready you might want to remove the choke parts
    but do not mill the choke tower off that will make bad air across the air bleeds and can make problems
    Thanks
    Ricky,Thanks for your input,I guess the big ?s I had is,in racing app is it best to plug sec pwr valve and jet-up,and would i gain by putting 1 to 1 sec opening kit for restarts on circle track dirt car?Thanks Tim

  4. #4
    rickyr Guest

    Default

    The 4776 only has a pri. power valve
    no sec. PV
    pri. jets are 66 and the sec. jets are 73
    you might try part # 20-122 adjustable sec. linkage, and play with when the sec. open, I do not think one to one
    but maybe get them to open a bit sooner
    Thanks

  5. #5
    roudabush Guest

    Thumbs up Re

    I have been runing 72s or 73s in front 75s and 6s in back ,and havent had back bowl off lately but it is pluged a/pwr valve as you said ,going to confirm Monday.Plugs always look a tad wet,even w/MSD6 and 59 champions.Dont think i ever seen a truely BRN or TAN plug.Just dont want to high RPM Lean out.Ill kick in Secdar @40 Deg of Primary and be happy w/that.Engine won the last race so aint runnin to bad.Thanks Dude.......Tim R

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