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NGK Iridium IX Spark Plugs (Mid 08-10 Mustang GT)

Item 64068
AmericanMuscle no longer carries the NGK Iridium IX Spark Plugs (Mid 08-10 Mustang GT). Please check out 2015-2023 Mustang Spark Plugs & Spark Plug Wires for an updated selection.
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    Video Review & Installation

    These are the NGK iridium spark plugs for mid-2008 to 2010 GT and Bullet Mustangs. These NGK iridium spark plugs have a heat range of six, which is the same heat range of the factory plugs. Now being the same heat range means that these plugs are gonna be a good option for those that have a stock setup or one with basic bolt-ons. If you have a forced induction Coyote, you'll need to make sure that you go with a colder heat range plug. So, a turbo, super charger, nitrous build would need the step cooler plug. But if you have a naturally aspirated build and you're looking for a performance plug, I would suggest these plugs, since they have the same heat range and these are a good stock replacement upgrade. I will say though, that these are for the Mustangs that are equipped with the brown coil boots only. The install for spark plugs is very easy on the Coyote. It's a one outta three wrenches in the difficulty meter, and you can plan on spending about a half an hour's time. So, heat range is something that's important to pay attention to when you're shopping for spark plugs. Different builds and setups require different heat ranges. It all depends on your mod list. The heat range of the plug is a range where the plug works well thermally. And of course your modifications, or lack thereof, will determine the temperature where the spark plug will be operating. You wanna 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 on this plug is a six, and the way NGK labels their plugs is 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 very high melting point which makes it perfect for performance-based applications. The core in the iridium tip are gonna be determining factors of the heat range of the plug. When it comes to price, you can expect to pay just south of the 100 dollar mark for a set of eight plugs. This is the same as what you can expect to pay for other brands of plugs, so I wouldn't say that the price is crazy here. Your other options include: Ford Performance, Autolite, Ford Motorcraft and Brisk makes an offering for boost that are also very close in price. So the NGK here isn't your only option, but they are your only option if you're specifically looking for an iridium plug. As far as the install goes, this is an easy install and it's a one outta three wrenches in the difficulty meter. You'll 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 putting some anti-sieze on the threads of the new spark plugs and make sure the plugs are all gapped the same before you install them. Once you've swapped all of the plugs, reinstall the coil packs, plug them back in, and that's all it's gonna take. Wrapping things up here, these are the NGK iridium spark plugs for mid-2008 to 2010 GT and Bullet Mustangs. As always, you can check them out more online right here at

    Product Information

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


    • Iridium Tip for a Constant Stable Spark
    • Improves Fuel Economy and Lower Emissions
    • Heat Range: 6
    • NGK Part# ZNAR6IX-11; NGK Stock# 372
    • 12mm Thread Pattern
    • Sold as a Set of 8
    • Fits 2008-2010 GT and Bullitt Mustangs w/ Brown Coil Boots


    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) NGK Iridium IX Performance Spark Plugs are specifically designed for the 2008-2010 GT and Bullitt Mustangs equipped with Brown coil boots only.

    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


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