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NGK Iridium IX Spark Plugs; Heat Range 7 (03-04 Cobra; 07-14 GT500)

Item 64070
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Market Price $99.99 You Save 10% ($10.00)
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$89.99 (set of 8)

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Ship to: Ashburn - 20149
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      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • Perfect for Increased Boost
      • Iridium Tip for a Constant Stable Spark
      • Improves Fuel Economy and Lower Emissions
      • Heat Range: 7
      • NGK Part# TR7IX; NGK Stock# 3690
      • 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 high performance engine running smoothly and efficiently is important, so routinely replace your old weak plugs with a new set of NGK Iridium IX Performance Spark Plugs for constant reliable spark power. The Iridium IX plugs from NGK will provide improved throttle response, fuel efficiency, lower emissions, and will reduce fouling.

      Superior Materials. NGK Iridium IX Performance Spark Plugs feature a copper core electrode for its superior conductivity and an iridium tip (which is 6X harder than platinum) for it's extremely high melting point, perfect for keeping your Mustangs high-performance engine running at it's peak. And as an added bonus the Iridium IX plug features Trivalent Metal Plating for it's superior anti-corrosion and anti-seizing properties.

      Application. This set of eight (8) One Heat Range Cooler NGK Iridium IX Performance 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

      MPN# 3690


      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (7)

      Write a Review

      Ratings Summary

      4.7 out of 5 overall rating from 7 customers

      Installation Time: Less than 1 Hour

      • November 04, 2019

        5 2012 GT500 - ChristopherH Installation Time: Afternoon

        NGK Iridium IX heat range 7

        Replaced ngk tr6 plugs with these. I’m running about 13-14 lbs of boost on stock blower. They came gapped around .039. I gapped mine at .033. They work great. No hesitation at all. Feels like I have full power. Thanks AM. Definite thumbs up for these plugs.

        Helpful (0)
      • June 02, 2019

        5 2014 GT500 - Erikbaseball1 Installation Time: Less than 1 Hour

        Perfect for increasing boost

        Definitely need to get this if you plan on increasing boost perfect product extremely happy.

        Helpful (0)
      • April 30, 2018

        5 2013 GT500 - EdwinSVT Installation Time: Less than 1 Hour

        nice n sparky

        had put them on recommended by my tuner (my application gapped at .028) for the tune i was going to run and they work awsome in my gt500

        Helpful (8)
      • April 12, 2018

        5 2007 GT500 - TerryS Installation Time: Less than 1 Hour

        Reliable Spark Plugs

        The plugs are well made and arrived quick. I am running 12 lbs of boost in my GT500 and needed a colder range plug sp I figured I would try these. I gapped them to .032 and installed them in less than an hour. I've noticed better throttle response and better fuel economy. I would recommend these to anyone looking for a better than stock plug.

        Helpful (7)
      • February 28, 2016

        4 2009 GT500 - kaznah Installation Time: Less than 1 Hour

        GT spark

        I recently purchased these spark plugs for two reasons. 1st- because I installed some upgrades and my GT 500 started missing after about a month and a few miles. 2nd - The current ones were just a little worn and gapped wrong. Yes, I closed the gap on the old ones and improved the problem. When I installed the Iridium plugs there was noticeable difference in performance. I would recommend these to anyone that may have installed bolt-ons that increased the amount of boost from factory levels.

        Helpful (9)
      • May 29, 2015

        5 2004 Cobra - termi04 Installation Time: Less than 1 Hour

        spark plug

        this is a great product I recommend this to every Cobra owner. you could tell the difference in this product

        Helpful (8)
      • June 10, 2013

        4 2011 GT500 - BigBearGT500 Installation Time: Less than 1 Hour

        Good product, easy install

        Decided to change my plugs out at 30K miles. Old stock plugs had lots of carbon build up and looked pretty worn out. Getting the old plugs out and new ones in was a breeze, but I took my time so finished it in about 2 hours. Didn't notice any performance gain, but acceleration is smooth. AM prices on these plugs is very competitive.

        Helpful (9)

      Questions & Answers (1 answers)

      1 Top Rated Question

      would these be good for a boosted mach 1 running about 10 psi?

      • We recommend checking with your tuner as they will be able to advise which spark plugs will be best suited for your vehicle.

      Helpful (0)
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      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (8) Spark Plugs
        Hardware included:
      • None Required

      Tech Specs

      Will It Fit My Mustang

      • Cobra - 03, 04
      • GT500 - 07, 08, 09, 10, 11, 12, 13, 14

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