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Thread: mixed rocker arms?

  1. #1

    mixed rocker arms?

    I have a newbie type question for you experts out there. I have noticed some mixed ratio rocker arm sets out there (1.5-1.6) and was wondering what the purpose for this is? :?:

  2. #2
    Senior Member RACING JUNKIE
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    Some people run 1.5 on the exh. and 1.6 on the int. or visa/versa if they have a small lift cam. If that is /was what was happening you should have 8 1.5's and 8 1.6's with your set, if you dan't have an equal number then it's time to get another set of rockers.

    JMO

    Zip.

  3. #3
    Senior Member RACING JUNKIE
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    Re: mixed rocker arms?

    Quote Originally Posted by craigs55
    I have a newbie type question for you experts out there. I have noticed some mixed ratio rocker arm sets out there (1.5-1.6) and was wondering what the purpose for this is? :?:
    Like Zip said, its to change the lift on one side or the other
    David Lanning
    IHRA NHRA 387B

    Fleenor Racing Transmission
    419-280-1406
    Lanning Electric
    Complete Drag Car Wiring
    APD Race Engines
    www.apdracing.com

  4. #4
    Senior Member MASTER BUILDER
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    Some single carb motors will pick up some HP with more lift on the corner cylinders because of being farther from the carb.I have 1.65 in&ex on 1 2 7&8 and 1.6 in&ex 3 4 5&6 single 4 sbc.Back to back test chaging from all 1.6 pick up just .02 Bill.

  5. #5
    Junior Member SHOW GUEST
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    valve lift

    The whole idea is to get the valve open.
    The higher ratio rocker accelerates the valve opening.
    Unless you already have an excessive amount of cam event, you should gain power by increasing the intake rocker ratio.

    In other words...If you do not gain power, you may already have more camshaft than you're using. Or the springs are insufficient.

  6. #6
    Senior Member RACING JUNKIE
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    According to what I've been told by some of the engine guys at Childress, on the new Gen IV SBC (NASCAR), they use a very low profile cam, flat tappet lifters and 1.9 rockers, combined with about 185# of seat pressure . . They won't say what the actual seat pressure is, nor the cam they run (Manhattan Project) but they're getting 9200+ rpm out of them for 500+ miles, WFO . .

    Something to experiment with, perhaps?


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