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NGK Iridium IX Performance Spark Plugs - Heat Range 6 (03-04 Cobra; 07-14 GT500)

Market Price $79.99 You Save 13% ($10.00)
Our Price

$69.99 (set of 8)

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  • Item 525003
  • MPN# 3689

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Features & Details

  • Perfect for Stock Boost
  • Iridium Tip for a Constant Stable Spark
  • Improves Fuel Economy and Lower Emissions
  • Heat Range: 6
  • NGK Part# TR6IX; NGK Stock# 3689
  • 14mm Thread Pattern
  • Spark Plug Reach 0.690"
  • 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) NGK Iridium IX Performance "Heat Range 6" Spark Plugs are specifically designed for the 2003-2004 SVT Cobra and 2007-2014 Shelby GT500 Mustangs that are running stock boost.

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

What's in the Box
  • (8) Spark Plugs
Installation Info
Tech Specs
Will it fit my Mustang?
  • GT500 - 07, 08, 09, 10, 11, 12, 13, 14
  • Cobra - 03, 04

People Who Bought This Item Also Bought

Most Helpful Reviews

5/5
Solved my problem!!

I installed these plugs on my 10psi supercharged 03 mach 1 and solved my surging issues that were happening at cruising rpms (2k or less), I gapped them to 34 and have had no more issues. Thanks AM!!

Helpful (1)

5/5
Shelby plugs

these took care of the misfire, detonation problems I was having with the upgraded mufflers and tune. runs much smoother and a bit faster. good call...thanks AM

Helpful (1)

Overall Rating 5 out of 5 stars
Read All 2 Reviews

Customer Photos

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5 Questions / 5 Answers

Ask a Question

Do these plugs come pre gaped from the factory? If not what is the recommended gap for 03 Cobra running stock boost?

KirkC

  • Hello, These spark plugs do come pre-gapped, however it is always best to double check. The recommended gap should be listed in your vehicle's manual. According to NGK, these spark plugs come gapped at .040.

    NoahG

Helpful (0)

Would these be okay on a forged and strokes 2001 Bullitt on nitrous?

Ro

  • The NGK Iridium IX Performance Spark Plugs could work for your build, however considerably more information would be needed to best assist you, such as total horsepower, and the size of the nitrous shot being used. Please contact our Customer Service Department so that we may discuss your build and come up with the best suggestion for you.

    Rob D

Helpful (0)

I have heard the NGK V power plugs do not last very long. Will these be comparable but last longer?

ChristopherH

  • Hello! These NGK Iridium IX Performance Spark Plugs - Heat Range 6 should last a long time, and are a very solid plug.

    JacobC

Helpful (0)

Will these work well with a 2001 gt, with kenne bell with 9psi of boost?

mitchyslick

  • Thank you for your question about the NGK Iridium IX Performance Spark Plugs - Heat Range 6 (03-04 Cobra; 07-14 GT500). Unfortunately, these would not work for a 2001 GT with a Kenne Bell.

    AMRich

Helpful (0)

Are these one piece or two like the stock ones?

Groomzee

  • The NGK Iridium IX Performance Spark Plugs are two piece spark plugs.

    KevinD92

Helpful (0)

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Customer Reviews (2) Write a Review

Overall Rating 5.0

out of 5 stars

Installation Time:Afternoon

  • Performance Gain 5 5
  • Fit 5 5



  • 5/5

    October 11, 2016

    Solved my problem!!

    I installed these plugs on my 10psi supercharged 03 mach 1 and solved my surging issues that were happening at cruising rpms (2k or less), I gapped them to 34 and have had no more issues. Thanks AM!!

    Gmantj

    Year: 2003 Submodel: Mach 1

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    September 12, 2014

    Shelby plugs

    these took care of the misfire, detonation problems I was having with the upgraded mufflers and tune. runs much smoother and a bit faster. good call...thanks AM

    waveblastr

    Year: 2011 Submodel: GT500 Tallahassee, FL, USA

    Helpful (1)

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