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LQ9

This is a discussion on LQ9 within the LS2/LS3/LS4/LSx forums, part of the Vehicle Specific category; Was wondering if anyone knows the gas mileage for a LQ9 bored to a 408 and does it run hot. ...

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    LQ9

    Was wondering if anyone knows the gas mileage for a LQ9 bored to a 408 and does it run hot. Would u recommend it for a every day hot rod driver

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    pajeff02's Avatar
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    '02 WS.6 / '07 Suburban

    The more power you make the more heat the engine generates. This being said, there are a couple of guys running 4-oh-whatever displacement engines in their F-bodies with no cooling problems that I have heard of. Shouldn't be an issue in a truck with the frontal area and larger radiator setup. You can swap in a cooler thermostat and reprogram the fans to come on sooner. The stock thermostat in most GM's are around 198 degrees these days.

    Gas mileage all depends on your right foot and final gearing. With an overdrive transmission you should be able to easily keep it in the mid-teens.

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    Junior Member Wagonmaster2's Avatar
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    black cherry
    1939 Chevy

    I know of two here locally that do not have overheating issues. I have a 6.0, but mine is stock bore and stroke.39-cruising-winder.jpg

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    Spaz is My Mentor SMWS6TA's Avatar
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    Navy Blue Metallic
    98 T/A w/a little mods...

    Quote Originally Posted by pajeff02 View Post
    The more power you make the more heat the engine generates. This being said, there are a couple of guys running 4-oh-whatever displacement engines in their F-bodies with no cooling problems that I have heard of. Shouldn't be an issue in a truck with the frontal area and larger radiator setup. You can swap in a cooler thermostat and reprogram the fans to come on sooner. The stock thermostat in most GM's are around 198 degrees these days.

    Gas mileage all depends on your right foot and final gearing. With an overdrive transmission you should be able to easily keep it in the mid-teens.














    Mine is a 403ci. No issues with cooling what so ever. I have a 165* T-stat, and do have the fans come on around 190*. I live in South AL where temps get in the high 90's to 100's in the summer. Still no issues.

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