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    Author Topic: Stock Compression Ratio 71 Cuda 383?  (Read 936 times)

    Offline Total BS

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    Stock Compression Ratio 71 Cuda 383?
    « on: April 29, 2006 - 11:27:38 PM »
    Hi gang,

    I am trying to order a ignition system for my 71 Cuda and the company is asking me what the stock compression ratio is to best supply what I need.  Can anyone help me out.  I have a 71 383 4-BBL, auto w/ A/C.  Any help would be appreciated.
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    1971 'Cuda 383
    1970 Chevelle SS LS6
    1999 Durango
    -New Joisey-


    Offline Ghost

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    Re: Stock Compression Ratio 71 Cuda 383?
    « Reply #1 on: April 29, 2006 - 11:33:34 PM »
    8.5 to 1.
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    Offline Cuda Cody

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    Re: Stock Compression Ratio 71 Cuda 383?
    « Reply #2 on: April 30, 2006 - 01:11:36 AM »
    In 1970 a 383 was 8.7:1 for a 2 bbl and 9.5:1 for a 4 bbl (per the factory manual).  Not sure why they would drop so much for the 71's?

    Is your engine still all stock?  If not, you're in the same club as I am.  You really have no way of being sure.  Changing the pistons, cam or heads can changes the compression ratio a ton!
    « Last Edit: April 30, 2006 - 01:28:23 AM by C O D Y »
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    Offline Total BS

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    Re: Stock Compression Ratio 71 Cuda 383?
    « Reply #3 on: April 30, 2006 - 10:14:41 AM »
    Thanks guys...

    Cody, as far as I know the only thing that was changed was the carburator and intake at some point. I just had the engine rebuilt to stock with a little cam upgrade which I have the paper work on.  That is why I am trying to figure out the original compression ratio so that they can put together the right package for my setup. Being technically inedpt, its not easy...lol
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    1971 'Cuda 383
    1970 Chevelle SS LS6
    1999 Durango
    -New Joisey-

    Offline FY1 RT SE

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    Re: Stock Compression Ratio 71 Cuda 383?
    « Reply #4 on: April 30, 2006 - 11:34:18 AM »
    A '71 383 magnum produced 35 hp less than the '70 magnum.
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    Offline Ghost

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    Re: Stock Compression Ratio 71 Cuda 383?
    « Reply #5 on: April 30, 2006 - 02:37:26 PM »
    Quote from: C O D Y on April 30, 2006 - 01:11:36 AM
    In 1970 a 383 was 8.7:1 for a 2 bbl and 9.5:1 for a 4 bbl (per the factory manual).  Not sure why they would drop so much for the 71's?

    Emissions regs.  Every HiPo engine, except the HEMI I believe, lost some compression.
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