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

1 Reviews
Our Price


(set of 8)
  • Item #525003
  • MPN# 3689

  • Market Price $89.99
  • You Save 22% ($20.00)
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  • 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
Will it fit my Mustang?
  • GT500 - 07, 08, 09, 10, 11, 12, 13, 14
  • Cobra - 03, 04

Customer Photos

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Q & A

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Are these one piece or two like the stock ones?

Groomzee Year: 2006 Model: GT

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Customer Reviews (1) Write a Review

Overall Rating 5.0

out of 5 stars

Installation Time:Afternoon

  • Performance Gain 5 5
  • Fit 5 5
  • Bang For Your Buck 5 5

  • 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


    Year: 2011 Model: GT500 Driving Style: Street / Strip 'Stangs I have owned: 3 Tallahassee, FL, USA

    Helpful (0) (0)

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