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

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

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  • Item 64068
  • MPN#372

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Features, Video & Details

  • 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

Review & Installation Video

Review & Install Video

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 americanmuscle.com.

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.

Fitment: 2008 2009 2010 Details

What's in the Box
  • (8) Spark Plugs
Installation Info
Tech Specs
Will it fit my Mustang?
  • Bullitt - 08, 09
  • GT - 08, 09, 10

People Who Bought This Item Also Bought

Most Helpful Reviews

5/5
Great Spark Plugs

These NGK Iridium IX Performance Spark Plugs only took two hours to replace and have gave my 09 Mustang GT three MPG better gas milage around town, also my car runs so smooth! Thanks America Muscle for ...

Read More
Helpful (4)

5/5
Very good

Easy DIY install and runs smooth, great idle and feels like it has the list power back l! Product looks great the only compliment to this would be new performance coils!

Helpful (3)

Overall Rating 5 out of 5 stars
Read All 27 Reviews

Customer Photos (1) Submit Your Photo

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15 Questions / 7 Answers

Ask a Question

Is the gap of these NGK plugs set to 0.40-0.50? It seems like a lot of people have installed their new NGK plugs without checking the gap but have had no problems.

ChristopherM

  • We do not have the spec at what these NGK plugs are set to out of the box, they would be close to factory spec but we always recommend double checking the plug gap before installation to ensure proper performance.

    AMjordan

Helpful (1)

Will the NGK Iridium plugs work with MSD coil plug set? Will these plugs work with MSD coil plug set?

ITALIANO

  • Yes it will

    nate401

Helpful (1)

What is a Brown Coil Boot? I see that I must have it to install these plugs so what are they? I have a 2010 GT

EBoss

  • The boot coil color changed some time in 2008 from black to brown. Your 2010 would have a brown boot. Hope this helps!

    LisaS

Show 1 more answer Helpful (1)

Can these fit on 2005 mustang GT?

HusainA

  • The NGK Iridium IX Performance Spark Plugs will only fit mid 08-10 GTs.

    VincentV

Helpful (0)

it says to drop 1 heat range for every 75-100 hp added. what is the factory heat range?

dbrening

  • The NGK Iridium IX Performance Spark Plugs would share the same heat range of the OEM plugs, coming in at heat range 6.

    Rob D

Helpful (0)

Will these fit my 06 mustang gt?

DuaneC

  • The NGK Iridium IX Performance Spark Plugs will only fit a mid 08-10 GT

    VincentV

Helpful (0)

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Customer Reviews (27) Write a Review

Overall Rating 5.0

out of 5 stars

Installation Time:Afternoon

Installation Cost:0-$100

  • Performance Gain 4.416667 4.4
  • Fit 4.833333 4.8



  • 5/5

    Installation Time: Afternoon

    November 08, 2012

    Great Spark Plugs

    These NGK Iridium IX Performance Spark Plugs only took two hours to replace and have gave my 09 Mustang GT three MPG better gas milage around town, also my car runs so smooth! Thanks America Muscle for the great price! Rich Stanley

    Lich

    Year: 2009 Submodel: GT Fort Walton Beach, FL, USA

    Helpful (4)

  • 5/5

    Installation Time: Less than 1 Hour

    July 27, 2012

    Very good

    Easy DIY install and runs smooth, great idle and feels like it has the list power back l! Product looks great the only compliment to this would be new performance coils!

    Allblackbullitt

    Year: 2009 Submodel: Bullitt

    Helpful (3)

  • 5/5

    Installation Time: Less than 1 Hour

    July 26, 2012

    A MUST HAVE!

    these are a must have cause for the price n time it takes to put them on it just great. also i have a 2010gt and almost about to hit 30k miles and the motor started to have some miss fires while driving the car little hard or starting the car at times. and now having these on for about a week now the car is running like new. you can hear n feel the difference once you turn on the car it jut great. gas mileage did go up and all threw the gears you can feel the difference especlly on 5th. but im really happy i went with these plugs. let me include as aways shipping was extremlly fast thanks AM!

    andycoll

    Year: 2010 Submodel: GT NY

    Helpful (3)

  • 5/5

    Installation Time: Less than 1 Hour

    February 26, 2017

    Great product

    I was really thinking of not doing my self since I'm close to 90k and the previous owner bever touched them but decided to go a head and change them out . Install was really easy just had to take my time getting them out. Car runs way better with these spark plugs. Worth every penny .

    JohnnyA

    Year: 2010 Submodel: GT

    Helpful (2)

  • 5/5

    Installation Time: Shop Install

    February 06, 2017

    NGK Iridium spark plugs

    I highly recommend these. It was a night and day difference from the factory spark plugs. The extra performance was immediately noticeable. I had them installed while i had all the fluids changed. Excellent product.

    Steve

    Year: 2010 Submodel: GT

    Helpful (2)

  • 5/5

    August 25, 2016

    NGK IX

    Easy install, more power, better idle, faster start up. I also installed the SR coils with these NGK IX plugs. Pulls a little harder from 3000-6700rpms.

    FstEddie

    Year: 2010 Submodel: GT

    Helpful (2)

  • 5/5

    February 06, 2017

    NGK iridium spark plugs

    Nice product combine with Grantelli 3v Street fighter coil packs seem to get great response on top end and fires up like a beast

    09slayer

    Year: 2009 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    December 31, 2016

    Great!

    The spark plugs are absolutely great. No problems whatsoever! Highly recommended!

    Frosty

    Year: 2010 Submodel: GT

    Helpful (1)

  • 5/5

    August 29, 2016

    NGK Iridium IX Performance Spark Plugs

    Smoothed out the idle and feels like there is a little more power on my 08 Bullitt, that has 32k miles. Well worth the purchase.

    Bob

    Year: 2008 Submodel: Bullitt

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    May 18, 2016

    Definitely recommend!

    Easy install, took about an hour and a half. The car felt like new, from a stop I could let up the clutch a little quicker, the shifts feel smoother, and it fells like the car is able to pull a little harder in every gear (especially in the higher gears). Overall very happy with the purchase.

    Cetter21

    Year: 2010 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    March 08, 2014

    Eh.

    Car was at 83k miles so I figured I would change out plugs. Took about an hour and luckily I didn't break any, so everything went smooth. The plugs I took out were still VERY clean, so I didn't notice much of a difference. Guess it's just an accepted maintenance cost.

    ConfusedGuy

    Year: 2009 Submodel: GT Fort Lee, VA, USA

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    October 01, 2013

    I really didn't think plugs would make a difference.

    My mustang is more powerful, smooth, and faster response with these plugs. Better than when I drove it off the lot brand new. So happy with these plugs. Note: I also added the Acel coil packs, which are great also.

    Mo2010

    Year: 2010 Submodel: GT Waldorf, MD

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    July 24, 2013

    Great replacement product

    Bought these plugs to do my 80,000 mile maintenance on my 2010 GT. Very easy install if you take your time and make sure to keep the area clean. Compressed air in a can helps a TON. Install time was only a couple of hours and there was an instantaneous improvement on drivability, mainly in the smoothness of the vehicles idle. Wouldn't say I felt too much power gain but thats not what I was after. Great product with a reasonable price.

    grabberbluemach

    Year: 2010 Submodel: GT Pontiac, MI, USA

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    July 07, 2013

    Excellent Spark Plugs

    Excellent product. I would recommend this to anyone who needs new spark plugs.Very easy to install. I was able to install within an hour.

    rangerbert

    Year: 2008 Submodel: GT Union City Pa

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    June 11, 2013

    They Spark

    I installed these plugs with a set of MSD COPs. The car now runs a lot smoother and sounds better as well. Definitely worth the few extra $$.

    DevGittinJr

    Year: 2009 Submodel: Bullitt Longview, TX

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    June 07, 2013

    ELGRANREY SAYS

    these plugs are great. I felt a VERY noticeable power gain and the car runs smoother than ever now.

    Tomas

    Year: 2008 Submodel: GT Newport News, Virginia

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    March 23, 2013

    Great product

    Definitely worth the money! Any other auto parts store would have sold me a cheaper set of spark plugs for the same price but not AM! I definitely feel a difference in performance and I've gained gas mileage. First time changing out spark plugs so it took me a little bit but the longest part was waiting on the liquid wrench to soak through. All in all an outstanding product! Thanks AM!

    GenoD

    Year: 2008 Submodel: GT Suffolk, VA, USA

    Helpful (1)

  • 5/5

    February 22, 2013

    Excellent Spark

    This product is worth its money. Just by itself installed you get your performance you lost through simply having them long miles on your stang. Its an easy remove and replace process But if you have you own tuner or would like to go to your own speed shop and have your car tuned and tweaked to get the absolutely most out of it that's a great idea too!

    virginiaBEAChBULLITT

    Year: 2008 Submodel: Bullitt Virginia Beach, VA, USA

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    September 22, 2017

    Awesome

    Add lost power from old spark plugs! Work perfect especially when 3 of mine were shot!

    TJ

    Year: 2010 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Less than 1 Hour

    September 05, 2017

    NGK without a doubt

    It was time to do some maintenance with my 07 which has an 08 motor in it thankfully. These plugs were all ready to go outside of the box and only took me about 30 minutes or even less to install. Super easy and she sounds much more smooth now. I wouldn't expect any performance gains but rather free up some power that was lost from worn out parts. But I would definitely recommend these to anyone that wants to replace their spark plugs on any 08 to 10 4.6.

    Cantcatchsilverbullitt

    Year: 2007 Submodel: GT

    Helpful (0)

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