440 compression ratio ?

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    Author Topic: 440 compression ratio ?  (Read 1795 times)

    Offline rusty dodge

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    • 74 challenger 440-727-3:55
    440 compression ratio ?
    « on: July 15, 2005 - 12:12:12 PM »
    The chilton manual I have lists the 72 440 as having 8.2:1 compression.

    So I was trying to detemine if that is the compression ratio of the '72-440 that i have is. I dont know the history of this engine, but I'm assuming it hasn't been changed.

    It has flat top pistons, and they are down in the bores about  .050"-.052". It probably came with open chamber heads, but I was planning on using closed chamber 915 heads.
    « Last Edit: July 15, 2005 - 02:25:22 PM by rusty dodge »
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    Offline gomangoRT/SE

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    Re: 440 compression ratio ?
    « Reply #1 on: July 15, 2005 - 04:14:24 PM »
    Dont quote me on this but I think the early closed chamber 915s are either 75 or 78 CC heads and that should step up your compession............again someone like Cryco and better address this one......those heads by the way have excellent swirl and combustion characteristics
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    Offline 1973_Challenger

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    Re: 440 compression ratio ?
    « Reply #2 on: July 15, 2005 - 07:08:52 PM »
    This what I am figuring with a piston that is .052 in the hole and a .04 gasket with a stock block and 906 heads

    Block Height   10.725
    Stroke                   3.750
    Rod Length   6.768
    Piston Height   2.030
    Deck height   0.052
    Bore                   4.320
    # of Cylinders   8
    Displacement   439.7
    Compression Ratio   9.185
    Head Volume   88.0
    Gasket Thickness   0.040
    Piston Volume   0.00
    Rod Ratio                  1.805
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    Offline 1973_Challenger

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    Re: 440 compression ratio ?
    « Reply #3 on: July 15, 2005 - 07:11:19 PM »
    This is what I figure with 915 heads

    Block Height   10.725
    Stroke   3.750
    Rod Length   6.768
    Piston Height   2.030
    Deck height   0.052
    Bore   4.320
    # of Cylinders   8
    Displacement   439.7
    Compression Ratio   9.999
    Head Volume   78.0
    Gasket Thickness   0.040
    Piston Volume   0.00
    Rod Ratio   1.805
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    Offline rusty dodge

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    • 74 challenger 440-727-3:55
    Re: 440 compression ratio ?
    « Reply #4 on: July 15, 2005 - 10:52:09 PM »
    Thanks for the info. Must be some type of calculator to use?
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    Offline Chryco Psycho

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    • 70 Challenger R/T SE 70 tube Chassis Cuda now sold
    Re: 440 compression ratio ?
    « Reply #5 on: July 16, 2005 - 03:02:24 AM »
    I like the closed Chamber heads & they will raise the compression approx 1 point as calculated , with closed chamber heads I would use the steel head gaskets with approx .020 thickness & try to take advantage of some quench as well
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