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Racing Spark Plugs (03-04 Cobra; 07-14 GT500)

Market Price $44.99 You Save 11% ($5.00)
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  • Item 525503

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Ship to: Ashburn - 20149
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    Features & Details

    • Perfect for Boost & Nitrous Applications
    • Chromium Nickel Alloy Tip for a Constant Stable Spark
    • Improves Fuel Economy and Lower Emissions
    • 1 Heat Range Colder
    • Autolite Part# AR103
    • 14mm Thread Pattern
    • Spark Plug Reach 0.708"
    • Fits 2003-2004 SVT Cobra and 2007-2014 Shelby GT500
    • Sold as a Set of 8
    High Performance. Keeping your Mustangs nitrous or force inducted engine running smoothly and efficiently is important, that is why it is critical to choose the correct spark plugs for your application. These Autolite Racing Hi-Performance Spark Plugs are one heat range colder than stock making them perfect for supercharged Mustangs that are running additional boost.

    Superior Materials. Autolite Racing Hi-Performance Spark Plugs feature a copper core electrode for its superior conductivity and a chromium nickel alloy tip for a constant stable spark, perfect for keeping your Mustangs high-performance engine running at it's peak.

    Application. This set of eight (8) One Heat Range Cooler Autolite Racing Spark Plugs are specifically designed for the 2003-2004 SVT Cobra and 2007-2014 Shelby GT500 Mustangs that are running more boost.

    Fitment: 2003 2004 2007 2008 2009 2010 2011 2012 2013 2014 Details

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (8) Spark Plugs
    Installation Info
    Tech Specs
    Will it fit my Mustang?

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        Questions & Answers (4)

        4 Top Rated Questions

        Will these work on a 03 gt?

        • These Autolite Racing Spark Plugs are intended for 03-04 Cobras and 07-14 GT500s. For a full selection of spark plugs for your 2003 Mustang GT, please click the link below.

        Helpful (0)

        Can These Spark Plugs Hold Up to 700 Hp ? Or no ? I need a spark plug that can because I have the 2.3 FRPP TVS blower on my car

        • Yes, you could use these spark plugs for this application and with this blower!

        Helpful (0)

        Hello, can this spark plugs be used on a 2003 Mach 1? car is literally stock, thanks.

        • The Autolite Racing Spark Plugs would not be ideal for your 2003 Mach 1, as these are one heat range below stock. This makes them ideal for boosted and nitrous applications, or naturally aspirated builds where horsepower has been significantly increased with both bolt ons, and engine work such as heads, cams, etc.

        Helpful (0)

        My Shelby book refers me to the emission control decal to get Spark Plug Gap. WELL; it refers me back to the Shelby Book.I see you mention Spark Plug Reach....Is this actually the GAP? I have a 2007 GT5OO.I have the AP103 Plugs...THANKS...

        • Spark plug gap and spark plug reach are slightly different. Spark plug gap would be a measurement of distance between the center and side electrodes on the plug, whereas the spark plug reach is the length of the plugs threads.

        Helpful (0)
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          Customer Reviews (5) Write a Review

          Overall Rating 4.8

          out of 5 stars

          Installation Time:Less than 1 Hour

          • Performance Gain 4.6 4.6
          • Fit 5 5

          • 5/5

            Installation Time: Less than 1 Hour

            April 05, 2019

            Great spark plugs

            Their racing spark plugs nuff said. Good for street and track. Gap to fit and speed away


            Year: 2010 Submodel: GT500

            Helpful (0)

          • 5/5

            Installation Time: Less than 1 Hour

            December 17, 2017

            Autolite spark plugs

            I was having a bogging/missfiring issue . These plugs fixed that on my 03 Cobra , I am only running 12 pounds of boost on my pores Eaton So I highly recommend this for anyone running low boost.


            Year: 2003 Submodel: Cobra

            Helpful (14)

          • 4/5

            Installation Time: Less than 1 Hour

            December 14, 2015

            1998 cobra 03 cobra long block

            The plugs when in nice and easy seem like my car idles a whole lot better clean burn smell to exhaust


            Year: 1998 Submodel: Cobra

            Helpful (14)

          • 5/5

            Installation Time: Less than 1 Hour

            November 19, 2015


            Very good product would recommend for any one running a lot of boost in ther car


            Year: 2008 Submodel: GT500 Colorado

            Helpful (16)

          • 5/5

            Installation Time: Less than 1 Hour

            October 06, 2014

            Dyno day

            Put these in my cobra before i threw it on the dyno. Ran perfect. Would use these for a long term spark plug if you daily drive ect. but they are the best to use for getting the highest dyno numbers.


            Year: 2003 Submodel: Cobra NJ

            Helpful (14)

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