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Kooks 1-5/8 in. Header and Catted X-Pipe Combo (99-04 GT)

Market Price $1,880.58 You Save 10% ($188.05)
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  • Item 65530

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    Features & Details

    • Increase Rear Wheel Horsepower and Torque
    • Includes Long Tube Headers w/ Matching Catted X-Pipe
    • 304 Stainless Steel Construction
    • High Flow Catalytic Converters
    • Free Flowing Mandrel-Bent Tubing
    • Fits 1999-2004 GT and Bullitt Mustangs
    Improve Horsepower And Torque. The Kooks Long Tube Header and Catted Shorty X-pipe combo kit for the GT and Bullitt Mustang will balance out the exhaust pressure to increase flow over the restrictive factory exhaust system resulting in more horsepower, torque, and better throttle response.

    Quality Construction. Manufactured from 1-5/8" mandrel bent 304 stainless steel tubing Kooks Long Tube Headers are TIG welded for strength, and feature a leak-free ball flange design to fit perfectly into the included 2.5" diameter 304 stainless steel Shorty X-pipe for excellent exhaust flow and performance.

    Natural Finish. These Kooks Headers feature a natural stainless steel finish, which provides an aggressive appearance to your engine bay. This is not a heat-resistant coating, AmericanMuscle recommends the use of Exhaust Heat Wrap for high performance applications.

    Recommended Upgrade. To realize the full power potential that this Kooks Long Tube Header and X-pipe Kit has to offer, AmericanMuscle recommends a custom tune with a Mustang Handheld Tuner to reprogram the vehicles computer (ECU) for proper operation.

    Application. This Kooks Long Tube Header and matching catted shorty X-pipe combo kit is designed specifically for the 1999-2004 4.6L GT and Bullitt Mustangs.

    Technical notes. Not legal for use on pollution controlled motor vehicles; intended for off road use only.

    Fitment: 1999 2000 2001 2002 2003 2004 Details



    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • Kooks Long Tube Headers
    • Matching Kooks catted shorty X-Pipe
    • Necessary Gaskets
    • O2 Extensions
    Installation Info
    Tech Specs
    Header Specifications
    Header Type: Long Tube Finish : 304 Stainless steel
    Type Mid Pipe Required: Kooks Shorty X Fitment: 1999-2004 GT and Bullitt

    Mid Pipe Specifications
    Style Mid Pipe: Shorty "X" Type Headers Required: Kooks Long Tube
    Piping Material: 304 Stainless Steel Piping Size: 2.5"
    Catalytic Converter: "Yes" Fitment: 1999-2004 GT and Bullitt
    Will it fit my Mustang?

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    Questions & Answers (9)

    5 Top Rated Questions

    will these work with an automatic transmission?

    • yes it would

    Helpful (1)

    Will this delete the EGR?

    • Yes, these headers will delete the EGR.

    Helpful (0)

    Will the kooks LTH X-pipe combo kit pass emissions testing in Texas?

    • This kit will not pass emissions since it is not legal for use on pollution controlled vehicles.

    Helpful (0)

    Will this combo work on a 2000 s281 sc convertible with borla stinger cat back?

    • The Kooks 1-5/8 in. Header and Catted X-Pipe Combo will have no issues working with your S281 SC.

    Helpful (0)

    will these headers require a oil filter relocation? and if i ever need to change the spark plugs after i install these headers, will i need to remove the headers to replace the spark plugs?

    • The Kooks 1-5/8 in. Header and Catted X-Pipe Combo will not require the oil filter to be relocated and you would be able to replace the spark plugs with the headers installed.

    Helpful (0)
    Post Your Question
    4 More Questions
    If i have buy this combo would it hinder the emmisions for CA? 1 answer
    Will this product work on the borla atak series? 1 answer
    is this combination applicable for borla stingers catback? 1 answer
    Ive herd that puting a 3" piping on a stock 02 gt i would lose power unless i have more mods i judt want to know if that is true? 1 answer

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    Customer Reviews (3) Write a Review

    Overall Rating 5

    out of 5 stars

    Installation Time:Weekend

    Installation Cost:$250-$500

    • Loudness / Volume 5 5
    • Exhaust Note 4.666667 4.7
    • Fit & Finish 4.666667 4.7
    • Bang For Your Buck 4.666667 4.7

    • 5/5

      March 01, 2019

      Kooks Sound Great! Can feel the additional power.

      i love my Kooks headers with catted X pipe. I was afraid that they were going to sound raspy with the X pipe as I have read repeatedly to go with an H pipe for the traditional muscle car sound. However, no H pipe was available for my 2001 Mustang GT. I was also concerned about going catted, but my previous exhaust was uncatted and I could always smell the exhaust fumes. These Kooks sound the best I have ever heard. No raspiness at all. A low rumble just like I was hoping for. I have them mated with Magnaflow Street catbacks. Out of the dozens of videos I have listened to, I honestly think my sound better than them all. I have some loss of torque in the low RPM's, but in the higher RPM's the additional power is very noticeable. The low end loss, however, may be due in part to the installation of an intercooler on my supercharger. I highly recommend Kooks.


      Year: 2001 Submodel: GT

      Helpful (0)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $250-$500

      July 14, 2017


      These pipes sound so freaking good at about 3k rpms would definitely recommend for anyone that likes a loud car lol


      Year: 2001 Submodel: GT

      Helpful (14)

    • 5/5

      Installation Time: Afternoon

      June 18, 2016

      Great Headers

      Great headers, Brought my car from a mumble to a rumble in a matter of hours (Self Installed) I'm glad to open my bonnet and see that shiny chrome.


      Year: 2001 Submodel: GT

      Helpful (17)

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