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NGK Iridium IX Spark Plugs; Heat Range 7 (11-17 GT; 12-13 BOSS 302)

Item 64064
AmericanMuscle no longer carries the NGK Iridium IX Spark Plugs; Heat Range 7 (11-17 GT; 12-13 BOSS 302). Please check out 2015-2022 Mustang Spark Plugs & Spark Plug Wires for an updated selection.
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    Video Review & Installation

    Stephanie: Hey guys. Stephanie with, here with the review of the NGK Iridium spark plugs for 2011 and newer GT Mustangs and 2012 to 2013 Boss Mustangs. These NGK Iridium spark plugs have a heat range of seven, which is one heat range cooler than the factory plug. Being a cooler plug, these plugs are going to be a go to option for those forced induction coyotes out there or a nitrous car. So, turbo, supercharger and nitrous build would need the step cooler plug. If you have a naturally aspirated build and you're looking for a performance plug, I would suggest the NGK laser Iridium plugs, because those are still at a heat range of 6. Which is what you need for an NA car. So, heat range is something that's important to pay attention to when you're shopping for a spark plug. Different builds and set-up require different heat ranges, it all depends on your mod list. The heat range of the plug is where the plug works both thermally and of course your modifications or lack there of, will determine the temperature where the spark plug will be operating. You want to make sure you're getting a plug in the right heat range so the plug can function normally and so you won't have fouling or pre-ignition. The heat range of these plugs is seven, and the way NGK labels their plugs is kind of opposite. The lower the number, the hotter the type of plug. The higher the number, the cooler the type of plug. These spark plugs still have a copper core electrode and the iridium is in the tip of the plug. Iridium is a very strong material and has a high melting point, which makes it perfect for the performance based application. The core and the iridium tip are going to be the determining factors of the heat range of the plug. When it comes to price, you can expect to pay just south of the hundred dollar mark for a set of eight plugs. This is the same as what you can expect to pay for other brands and plugs for forced induction cars, so I wouldn't say that the price is crazy here. Both Ford Performance and Brisk, make offerings for boost and they're very close in price. So, the NGK here isn't your only option, but they are your only option if you are specifically looking for an iridium plug. As far as the install goes, this is an easy install and it's a one out of three wrenches in the difficulty meter. You need a few tools and some anti-seize for the spark plug threads. The coils will need to come off, so you can disconnect the electrical plugs and unbolt each coil pack. Once the coil packs are out of the way, you have access to the spark plugs. If you want you can use some PB Blaster, to help loosen the plugs up before you dive in with your socket to remove the plugs. I would suggest pulling one out at a time and replacing each old plug with a new, freshly gapped plug with anti-seize on the threads. Rinse all the coil packs, plug them back in and that's all it's going to take. Wrapping things up here with the NGK Iridium spark plugs, these plugs have an iridium tip and heat range of seven. Which makes them a colder plug. They're perfect for forced induction or nitrous cars. As always, you can check them out more online right here, at

    Product Information

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


    • Perfect for Nitrous and Force Inducted Engines
    • Iridium Tip for a Constant Stable Spark
    • Improves Fuel Economy and Lower Emissions
    • Heat Range: 7
    • NGK Part# LTR7IX-11; NGK Stock# 6510
    • 14mm Thread Pattern
    • Fits 2011-2017 GT and 2012-2013 BOSS Mustangs
    • 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 as an upgrade for nitrous or force inducted 2011-2017 GT and 2012-2013 BOSS Mustangs equipped with the 4 valve 5.0L Coyote engine.

    CA Residents: WARNING: Cancer and Reproductive Harm -

    Installation & What's in the Box

    Installation Info

    What's in the Box

    • (8) Spark Plugs

    Tech Specs


    Customer Reviews (100+)

      Questions & Answers

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