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NGK Iridium IX Spark Plugs (79-82 5.0L; 87-93 5.0L; 94-95 GT)

Item 64005
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Market Price $79.99 You Save 13% ($10.00)
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$69.99 (set of 8)

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      Product Information

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


      • Iridium Tip for a Constant Stable Spark
      • Improves Fuel Economy and Lower Emissions
      • Heat Range: 4
      • NGK Part# 7559
      • Fits 79-82 5.0, 87-93 5.0 LX/GT, and 94-95 GT
      • 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 Spark Plugs are specifically designed as a direct fit replacement for the 1979-1982 5.0 V8, 1987-1993 5.0 LX/GT, and the 1994-1995 GT Mustangs equipped with the 5.0 liter V8.

      Fitment: 1979 1980 1981 1982 1987 1988 1989 1990 1991 1992 1993 1994 1995 Details

      MPN# 7559

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (27)

      Write a Review

      Ratings Summary

      5.0 out of 5 overall rating from 27 customers

      Installation Time: Afternoon

      Installation Cost: 0-$100

      • July 23, 2019

        5 1993 LX - jimmyv1 Installation Time: Less than 1 Hour

        Easy Install, Nice Upgrade

        NGK Iridium plugs came with correct gap and ready for install. Idle quality is improved and looking forward to longevity of these plugs.

        Helpful (1)
      • December 02, 2018

        5 1991 GT - IanB Installation Time: Less than 1 Hour


        Very nice plugs. Fire rapidly and these are a great addition for your car

        Helpful (2)
      • September 02, 2018

        5 1994 GT - DougH Installation Time: Afternoon

        Plug Replacement

        Job went smoothly factory plugs in car for last 24 years slowed job a bit they were done. New plugs wires and cap rotor night and day.

        Helpful (2)
      • June 30, 2018

        5 1992 GT - ChrisL Installation Time: Less than 1 Hour

        Looks good and works like a champ.

        Was time to do a full tune up on the car. Wanted to upgrade the plugs. These work have no problem.

        Helpful (5)
      • June 03, 2018

        5 1989 LX - Al Installation Time: Less than 1 Hour

        NGK Iridium lX

        Absolutely love the Iridium plugs Would recommend to everyone Great prices

        Helpful (5)
      • May 26, 2018

        5 1989 GT - JohnV Installation Time: Less than 1 Hour


        Sparks really work for foxbody, both in response and power! Felt a difference right away, throttle feels more responsive!

        Helpful (4)
      • November 30, 2017

        5 1994 GT - ThadiusB Installation Time: Less than 1 Hour

        1994 mustang gt NGK Spark plugs

        NGK performance Plugs work great! Will buy again if needed.

        Helpful (5)
      • October 16, 2017

        5 1989 GT - Armadag Installation Time: Afternoon


        These Sparks really livened my Fox up, both in response and power!

        Helpful (5)
      • August 23, 2017

        5 1990 LX - RyanR Installation Time: Less than 1 Hour

        Great Spark Plugs!

        I replaced my distributor cap and rotor, plug wires, and decided to change the plugs too while I was in there. The plugs I took out weren't bad at all, maybe a few thousand miles on them, but wow my car idles so much better and the engine runs so much smoother in general. You can't go wrong with these NGK iridium plugs I have them in my ranger as well. The difference is night and day

        Helpful (5)
      • June 08, 2017

        5 1994 GT - RobertO Installation Time: Afternoon

        spark plug

        Very easy to install. Several people will still say go with motorcraft because its what ford takes and I was seconding guessing this product but after installing, I notice a big differents in gas, ignition and so forth. Honestly it was worth the cash.

        Helpful (7)

      Questions & Answers (9 answers)

      5 Top Rated Questions

      I have a 1994 mustang gt with an e303 cam and gt40 heads. Will they still work great??

      • Yes, these would be a great match for your application.  

      Helpful (0)

      Will these plugs work with the gt40x heads?

      • Yes, these spark plugs would work with the GT40X heads.

      Helpful (0)

      Will these work well for TFS Aluminium heads on a 306 Dart Block pushing a Vortech at 10 PSI?

      • Unfortunately we do not have enough information to determine how these NGK Iridium IX Performance Spark Plugs would work with your setup. Please contact our Customer Service department, or your tuner so that your complete setup can be discussed, and a spark plug recommendation can be made.

      Helpful (0)

      I have a 1992 347 with stock block eldlebrock rpm performer heads will these work and what shoukd the gap setting be.

      • A custom setup such as the one you have may require careful testing and gapping, I would contact a local shop that specializes in performance tuning in order to determine the proper heat range and gap for your application before ordering the NGK Iridium IX Performance Spark Plugs.

      Helpful (0)

      Would these work for a 1985 5.0 Gt convertible?

      • For your 85 GT, you will need the NGK Iridium IX Performance Spark Plugs (83-85 5.0L), item # 64017, (

      Helpful (0)
      Post Your Question
      4 More Questions
      What spark plugs would you recommend for my boosted 5.0 running 5-7 pounds and a mild top end and stock bottom 1 answer
      does anyone know that gap size they come in i know tthey come pregapped 1 answer
      Anti-seize, yes or no? Should I use anti-seize with these or not and which one do you recommend? 5 answers
      Spark Plug Gap? Are the plugs already gapped or will i need to gap them? 4 answers

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (8) Spark Plugs

      Tech Specs

      Will It Fit My Mustang

      • Cobra - 93
      • Cobra R - 93
      • GT - 87, 88, 89, 90, 91, 92, 93, 94, 95
      • LX - 87, 88, 89, 90, 91, 92, 93
      • Other - 79, 80, 81, 82

      Fits 5.0L V8's Only

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