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NGK Iridium IX Performance Spark Plugs (93-01 Cobra; 96-04 GT, Mach1; 98-04 V6)

62 Reviews
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(set of 8)
  • Item #64007
  • MPN# 7164

  • Market Price $79.99
  • You Save 13% ($10.00)
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  • Iridium Tip for a Constant Stable Spark
  • Improves Fuel Economy and Lower Emissions
  • Heat Range: 5
  • NGK Part# 7164
  • Fits 93-01 Cobra, 03-04 Mach 1, 96-04 GT/Bullitt and the 98-04 V6 Mustangs
  • 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 1993-2001 SVT Cobra, 2003-2004 Mach 1, 1996-2004 GT/Bullitt and the 1998-2004 V6 Mustangs.

Fitment: 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Details

What's in the Box
  • (8) Spark Plugs
Installation Info
Will it fit my Mustang?
  • Bullitt - 01
  • Foxbody - 93
  • Mach 1 - 03, 04
  • V6 - 98, 99, 00, 01, 02, 03, 04
  • Cobra - 94, 95, 96, 97, 98, 99, 01
  • GT - 96, 97, 98, 99, 00, 01, 02, 03, 04

Most Helpful Reviews

High quality, perfect.

These plugs are very high quality. Replaced my ford motorcraft plugs and felt/noticed a small difference. Runs smooth, idles great, accelerates better w/o hesitation. No change in gas milage however. They ...

Read More
Helpful (2)

a nice upgrade

Together w/ screamin' demons coil packs and ford racing 9mm high performance spiral wires, my stangs fuel mileage seems to have improved. Didnt really feel a power difference and a week later my alternator ...

Read More
Helpful (1)

Overall Rating 4.8 out of 5 stars
Read All 62 Reviews

Review & Install Video

Well, here it is, our new project car, and as you can see I use the term new very loosely, you Fox body folks have been asking for it, so we’re going to give you a build unlike anything we’ve ever done before, we’re going to do a complete restoration on our 93 GT convertible, and you guys are going to be with us every step of the way. So what are our plans? Well, to say this thing is a little rough, would be the understatement of the century, we need to tackle just about everything there is on this car, I’m talking bodywork, paint, interior, headlights, and what’s left of our top just to name a few. Obviously we’re fans of just about every Mustang under the sun however there are a few that really get us going. One of these is the 93 Mustang Cobra, this was one of the first cars offered by Ford’s SVT division, and really set the tone as far as factory performance tuning is concerned however there was one problem, it was never offered in a convertible so we’re going to actually have a little fun with this build and make something we wish Ford had offered from the factory, we’re going to make our very own Mustang 93 Cobra convertible, which should really turn our tired old Fox into one bad little street machine. Before we get into the fun stuff, we need to take care of some much needed maintenance here on our 93, mainly the worn out and the 100000 plus drive train and body. So that’s the goal with this first step, we’re going to get our GT running like new again, and get the car ready for paint, because…yeah, we got a lot of work to do, so let’s get to it. Alright, 100000 miles of burnouts and hard launces has not been nice to our factory clutch, because it’s absolutely shot, so this is one of those areas where we’re not only going to freshen up, but we’re also going to upgrade, now our upgrade comes in the form of this Exedy Mach 350 stage 1 clutch, and the SR Performance clutch adjuster kit. This kit will replace our old, worn out, gummed up factory cable with this brand new adjustable cable as well as strengthen the weak plastic factory clutch quadrant with this brand new Billet piece. Basically we’re strengthening our overall shifting experience. Besides our beat clutch, our 302 motor is running extremely rough, we’re misfiring all over the place, and the power just isn’t there like it should be, so we’re going to give our motor a serious tuneup. Ryan and I are in the process of installing these iridium plugs as well as a new set of wires as well, on top of that we’re also doing a brand new distributor cap and rotor, and finally a brand new serpentine belt. All these parts should really get our 5.0 firing on all 8 cylinders again. As a little pointer for you whenever you’re doing a tuneup, we recommend using a little anti-seize on all your threads, just because you don’t want a stuck spark plug in your block. In addition, go ahead and throw a little dielectric grease on all your contacts, it’ll just help keep any excess moisture out. Unfortunately our slipping clutch and misfires are only part of the problem, when we were on the way back to the shop we noticed are car was running a little hot so we decided to overhaul our entire cooling system just to be safe. We’re ditching our factory radiator and mechanical fan in favor of this aluminum performance unit from Mishimoto, along with one of their electrical fans. This electrical fan will not only keep things cool, but by ditching that mechanical fan, we’re also going to free up some drag on our accessory belt, which in turn should free up some extra horsepower. To wrap up our entire cooling package we’re going with a brand new thermostat from Mishimoto, along with a new set of hoses from Ford Racing. Of course we have some performance stuff lined up after we get the car back from paint, but in the meantime we have to address this Frankenstein intake we found on the car, we’re going to replace it with this brand new SR Performance cold air intake which, besides giving us a nice little bump in power and sound, will more importantly get rid of this eyesore underneath the hood. Before we get out of the hood completely, we wanted to further reduce the parasitic drag on our accessory belt, so we decided to install this SR Performance smog pump delete kit. Could we run a smaller belt and eliminate the pump completely? Probably, but we wanted to do it right the first time, and clean up the engine bay in the process. Now that we’ve taken care of some necessary maintenance, let’s get to the next big part of the first stage of our resto. The only thing worse than the actual running condition of our GT is the physical condition, I’m not going to lie, this thing is pretty rough in just about every way, but that’s about to change, we’re going to send our GT off for some serious bodywork that includes a brand new paint job, but first, we need to take care of some problem areas. Some of these problem areas include a brand new set of smoked, one piece headlights, a new fender and a rear deck lid panel just to name a few but that’s not all that exciting, this is what’s going to turn our dream build into a reality, we’re going to outfit our 93 GT with a complete Cobra style body kit, along with this Cobra style wing, which when we’re done with our build, should turn our stock 93 vert, into one of the baddest, and possible one of the only, Foxbody convertible Cobras around. Well, that wraps up the first stage of the restoration here on our 93 GT, we took care of some much needed maintenance and got the car ready for the body shop, when we get the car back from paint, we’re really going to start having some fun with the interior and exterior styling, and of course give the car some much needed performance to back up that Cobra appearance, but in the meantime, I’m on my way to paint.

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9 Questions / 8 Answers

Ask a Question

Heat Range? It says the heat range is much colder/hotter is that over stock plugs? I'm looking for slightly cooler plugs to help with slight engine ping.


  • check out this chart. There seems to be no industry standard, only what is set by each manufacturer. 5 from NGK seems to be on the higher side of the scale though


    Good Answer (3) (0)

Answer This Question I need this answered (0) (0)

Stock Wires Will these work with stock conductor wires?


  • yes you can. You'll see better gains by matching them with better wires though.


    Good Answer (1) (0)

Show 2 more answers Question Resolved

How often should I replace these spark plugs?


  • these plugs are rated to last just as long as the standard plugs the car comes off the assembly line with. so check your owners manual for proper mileage and maintanence schedules. however, my recommendation would be about every 30k miles. thats what i do. and i never notice any lag or misfire from fowled plugs.


    Good Answer (0) (0)

Answer This Question I need this answered (0) (0)

Can this work with SR Performance Shock Coil On Plug Kit (99-04 GT)?


  • The NGK Iridium IX Performance Spark Plugs will work with the SR Performance Coil On Plug Kit, item 525008.


    Good Answer (0) (0)

Question Resolved

Are these good to use for supercharged applications?


  • If you're running boost, you will want a high heat range spark plug. If you're running very mild boost, I suggest a spark plug with at least a heat range of 6. If you're going to be running high boost, you will want a heat range of 7 and higher. This spark plugs only have a heat range of 5. You can use them, but it is not suggested.


    Good Answer (0) (0)

Question Resolved

Can these be used with a Procharger?


  • The NGK Iridium IX Performance Spark Plugs would be best as a replacement spark plug. We would recommend at least a one step colder spark plug, or perhaps a two step colder for forced induction applications.


    Good Answer (0) (0)

Question Resolved

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Customer Reviews (62) Write a Review

Overall Rating 4.8

out of 5 stars

Installation Time:Less than 1 Hour

  • Performance Gain 4.307693 4.3
  • Fit 4.925 4.9

  • 5/5

    September 22, 2016

    Awesome buy

    They fit perfect...would recommend this product. love shopping with AM


    Year: 1998 Submodel: GT

    Helpful (1) (0)

  • 5/5

    Installation Time: Afternoon

    February 04, 2016


    I installed these with MSD spark plug wires and a MSD coil pack, and the car runs smoother than I ever thought possible! No, it doesn't make your car super fast, but it definitely makes it more enjoyable to drive. Thanks American Muscle!


    Year: 2002 Submodel: V6 Leawood, KS

    Helpful (1) (0)

  • 5/5

    Installation Time: Afternoon

    May 16, 2015

    Good Spark, car starts and idles perfect overtime.

    I was noticing that my Mustang was taking longer to start especially on cold mornings so I bought these plugs after reading that they can help and sure enough she starts up right away overtime now. They also helped with how the car idles and throttle response I think is improved too. Just make sure that you torque each one to the specifications because I've heard too many stories of these 4.6 Liters blowing the plugs out.


    Year: 2004 Submodel: GT Hooper, UT

    Helpful (1) (0)

  • 4/5

    Installation Time: Afternoon

    July 21, 2014

    cleans up exhaust fumes

    after installing these plugs my exhaust doesn't stink, and my idle is much smoother ( my old properly gapped ) plugs only had 12,000 miles on them. wish I would have installed these instead of those. these were installed in my cobra kit car with 5.0 from a 91 GT with 93 cobra upgrades


    Year: 1993 Submodel: Cobra Surfside Beach, SC, USA

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    November 16, 2012

    great product

    My engine was running a little rough so i installed these spark plugs and they definitely helped smooth it out a little. helped with throttle response as well. the old ones were shot though so it makes sense these helped so much.


    Year: 1996 Submodel: Cobra PA

    Helpful (1) (0)

  • 5/5

    Installation Time: Afternoon

    August 05, 2012

    Good Quality Plugs

    I installed these plugs matched with MSD Cops and they are great. They solved a hesitation/sputtering problem i was having with my recently purchased GT and also restored some lost power. I am hoping with the steep price on these plugs that they will last longer and keep working better than the stock motorcraft plugs.


    Year: 2002 Submodel: GT New Jersey

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    January 20, 2012

    Silky Smooth

    They really smoothed out the rpm band. A bit expensive but I'd say they're worth it. They even came pre-gapped.


    Year: 2001 Submodel: GT chicago, IL

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    September 09, 2011

    a nice upgrade

    Together w/ screamin' demons coil packs and ford racing 9mm high performance spiral wires, my stangs fuel mileage seems to have improved. Didnt really feel a power difference and a week later my alternator went out -_- But after putting in a new one the voltage is steady where as it was jumpy before and the car idles GREAT.


    Year: 1996 Submodel: GT Kissimmee, FL

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    August 31, 2011

    High quality, perfect.

    These plugs are very high quality. Replaced my ford motorcraft plugs and felt/noticed a small difference. Runs smooth, idles great, accelerates better w/o hesitation. No change in gas milage however. They are made in Japan and make the motorcraft plugs look cheap.


    Year: 1997 Submodel: GT Denver

    Helpful (2) (0)

  • 5/5

    May 21, 2011

    ngk spark plugs

    i love these spark plugs. my engine was bogging and kinda hesitant but now runs like a champ haven't lost a race yet with theses new spark plugs. best investment you can buy. only problem was the fourth plug but just had to take a cover off. they come pregaped so no having to fool around with gaping plugs


    Year: 1997 Submodel: GT

    Helpful (1) (0)

  • 5/5

    February 17, 2011

    spark plugs

    These plugs are great. Better start ups, lower idle and lower rpm's in every gear which leads to a little better mpg. Would tell anybody to buy.


    Helpful (1) (0)

  • 5/5

    May 25, 2010

    spark plugs

    these spark plugs are good for stock or modified mustangs they just wake the muscle up from sleeping so much better than regular plugs a must just for some low end maintanence


    Helpful (20) (2)

  • 5/5

    February 04, 2011

    Best Plugs!

    My '01 Cobra had been having hesitation problems for a few months. Basically, it would seem to stutter at around 1900 rpm's. No one was able to figure out my problem and I was told that I would need a valve job. I replaced my plugs with the NGK Iridiums, and along with an oil change and a cleaned MAF and throttle body, the hesitation went away!!! I also noticed an increase in overall average MPG's. I highly recommend these plugs for any mustang!

    Fernando Pena

    Year: 1991 Submodel: Cobra

    Helpful (21) (3)

  • 5/5

    October 05, 2009

    Oh Yea Baby

    This plugs are awsome, I just put them on my GT Mustang and estan con toda su madre!!!.

    Tu Macho

    Helpful (31) (8)

  • 5/5

    August 28, 2010


    Better then origional ones, better mpg, smoother ride, better start.

    chris norman

    Helpful (12) (1)

  • 5/5

    March 29, 2010


    used with gms hot street coils on 01 cobra, it does what its supposed to


    Year: 2001

    Helpful (12) (1)

  • 5/5

    May 11, 2010


    Great product! Noticed better throttle response, better idle, and picked up a little better from the hole; didn't hesitate below say 1,800 RPM.


    Helpful (19) (5)

  • 5/5

    February 11, 2010


    does what its designed to do, get a good spark every time. not sure if its worth the price but it is a great produt


    Helpful (7) (2)

  • 4/5

    Installation Time: Afternoon

    July 06, 2013

    Overall satisfied ...

    The plugs definitely look sturdier. I use to use autolite. Compared to the old autolites that were in the engine, these were definitely a huge improvement. I BELIEVE the spark is more reliable and burns fuel more efficiently. However, that's more of a touchy-feely answer (no metrics - more of a SWAG).


    Year: 2000 Submodel: GT Austin, TX, USA

    Helpful (3) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    February 15, 2012

    Great Item

    Worth the bucks. Does the job. Would definitely recommend it.


    Year: 2003 Submodel: GT Los Angeles, CA

    Helpful (3) (0)

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