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  1. #16
    427
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    And yes EH. I think you are spot on. Nothing wrong with a single pattern for good grunt. ..

  2. #17
    Part of the furniture
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    Hi
    split pattern provide a flatter power/tq curve …………. single pattern has higher peaks

    split pattern can remove tq and hp below 4-5000rpm and transplant it above that point . The end of the hp dyno curve is lifted

    split pattern provide greater vacumm

    split pattern can make up for a restrictive exhaust [slightly]

  3. #18
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    Quote Originally Posted by EH179 View Post
    There's only 6* forward bias on it.
    Do you think a single pattern would be a better choice?
    Most of Clive Cams grinds for early head are single, as was a lot of group c stuff. So unless the intake port is heavily worked I would favour a single over a dual.
    I guess if you combine the dual pattern with the piston being a fair way down the bore for 9.5:1 with flat tops, you have a recipe for an inefficient engine.

  4. #19
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    Quote Originally Posted by Str8upal View Post
    Most of Clive Cams grinds for early head are single, as was a lot of group c stuff. So unless the intake port is heavily worked I would favour a single over a dual.
    I guess if you combine the dual pattern with the piston being a fair way down the bore for 9.5:1 with flat tops, you have a recipe for an inefficient engine.
    Even a stock engine, can benefit from a dual pattern cam due to the poor intake and good exhaust characteristics.
    But yes, as i said previously, piston to deck height on this one would be inefficient.

  5. #20
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    some great ideas guys i think its time to take it to a good engine builder who does great work with early head strokers. i feel the motor is 80% there just needs the right person to get it going as good as it can. in the end its only money

  6. #21
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    get in contact with hpepete or tk383, they'll find your missing power.
    p.b. 10;78@ 123.19mph. never late with a 308

  7. #22
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    A split pattern cam [ more exh duration ] does NOT provide more vacuum, post 16. It does the opposite because the extra exh duration increases overlap, the cause of the rough idle & reduced vacuum.

    The Holden V8's have got pretty efficient exh ports & a single pattern cam is the most likely to give best overall performance. These days, the smart guys are using reverse pattern cams that have more intake duration than the exh. Speak to Malcolm at CamTech.

    Isky Cams Website has Tech Tips. One of them is: is extra exh duration really necessary? You might be surprised for the reason that extra duration gets used...

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