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LS1 in a '74 Corvette Question

This is a discussion on LS1 in a '74 Corvette Question within the General Help forums, part of the LSx Technical Help Section category; In '74 they did not have catalytic converters. If I were to put an ls1 in that vette would i ...

  1. #1
    Never Drink and Derive Tonik's Avatar
    Join Date
    Jan 2006

    '99 SS

    LS1 in a '74 Corvette Question

    In '74 they did not have catalytic converters. If I were to put an ls1 in that vette would i need converters? For that fact would I need an exhaust at all or could I run open headers? Would the lack of back pressure with open headers even be beneficial, or would a full exhaust be a better idea?

    I do have a 74 corvette and am thinking crazy thoughts.... crazy like a fox...

    (The camaro and vette)
    New Pics! 99 Camaro / 74 'Vette

  2. #2
    Impwnded Smkn_TA's Avatar
    Join Date
    May 2007
    Davenport, Iowa

    Bright Red
    1999 Trans Am Ws6

    I would think not...depends on your state really. Here you can take them off a brand new car and not get in trouble for it. We do not have emissions test, and I have ran cars with none on it and been pulled over for loud exhaust, but they never fined me for the lack of cats. I know your asking because it is an old car, therefore it might be exempt.

    My question...ls1 engine, ls1 computer reads no cats, your throwing an engine code, even if you delete the rear o2's.

  3. #3
    Senior Member Zboner's Avatar
    Join Date
    Aug 2005
    cincinnati/northern ky

    99 SS

    if they were not OE equipment then i believe they are not needed

  4. #4
    Senior Member camarojunky74's Avatar
    Join Date
    Jun 2007
    corona ca

    white, white and pewter

    okay first, my 74 camaro which was a cali car had factory cats, but it was smog exempt as of 04 so i re did the whole car engine and all,

    for you you do not need cats and if you are planning on stick with the original exhaust that is a bad idea, im confused as to what you are doin i know you wanna put an ls1 in but what are your plans with the car,?

    and no, if you delete the o2's your pcm wont throw a code because that code wont be in the library,

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