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Kooks 1-3/4-Inch Long Tube Headers; Catted (15-20 GT)

Item 404493
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$1,888.62 (each)

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      Review & Installation Video

      These are the Kooks 1-3/4 long tube catted headers for 2015 and newer GT Mustangs. These are gonna be a good option for someone looking for a natural finish stainless steel long tube that keeps things street legal with a set of cats, and for someone that doesn't mind paying for the Kooks quality. This costs about $1,800 and I'm gonna call the install a three outta three wrenches in the difficulty meter.Long tube headers are gonna offer both performance and sound gains, but the end result of your headers will depend on the rest of your setup, while sound and performance gains will be impacted by the rest of your build. Getting into specifics here, the runners on these headers are 1-3/4 inch, which is slightly different than the 1-7/8 inch offering that Kooks offers. These headers also come with new catted pipes for you too, which is great news for those of you out there that want long tubes but also need to or want to keep things street legal. Of course, keeping a set of cats in place will make a difference when it comes to sound, but you still get a change in sound. These are a 304 stainless steel header that has a natural or raw finish, which is gonna be different than a chrome or ceramic coated header. It obviously doesn't have the polished appearance that a chrome header would have, and while these don't have the ceramic coating either, they are made from that 304 stainless steel tubing, so you won't have to worry about corrosion. Not to mention, you do get to see the beautiful welds and craftsmanship that these headers have since they do have that raw finish. And this is mandrel-bent tubing, which is gonna help with smoother air delivery.Moving along down the headers, the primary tubes then merge down to a 3-inch collector with scavenging spikes. Kooks always uses scavenging spikes just to make sure these headers will flow perfectly. And Kooks uses a ball and socket design here for a tight and leak-free fit. Then you have your connection pipes. These pipes are 3-inch, and this is where your cats are. So the connection pipe starts at 3 inches, but you can see that they do have a step-down adapter right here. These are gonna step down to 2-1/2 inches so you can run an aftermarket 2-1/2 inch cat-back or mid-pipe, or bolt right up to your factory cat-back. So just keep the 2-1/2 inch requirement in mind when you're picking out your mid-pipe or your cat-back.Touching on the install again, this one's gonna be a three outta three wrenches in the difficulty meter. Long tube headers are a difficult install. With that being said, that's gonna wrap up this review. Keep in mind that you can always check these out more online right here at

      Product Information

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


      • Long Tube Catted Headers
      • Precise OEM Quality
      • Outstanding Heavy Duty Construction
      • 1 3/4 Inch Mandrel Bent 304 Stainless Steel Tubing
      • Scavenger Spike Collectors for Maximum Air Flow Optimization
      • Limited Lifetime Warranty
      • Hard Degree of Difficulty Installation
      • Compatible with the 2015-2020 Ford Mustang GT


      Long Tube Catted Headers by Kooks. The Kooks 1-3/4 Inch Long Tube Catted Headers deliver gains in horsepower and torque with outstanding heavy duty construction, a precise OEM quality fit, and freer manifolds for long-lasting performance on the off-road.

      Specialized Construction. This product delivers exceptional airflow with a unique construction comprising of 1 3/4 inch mandrel bent 304 stainless steel tubing that connects to scavenger spike collectors for maximum airflow optimization.

      Warranty. Kooks provides a limited lifetime warranty, which protects purchasers from any defects in materials and workmanship.

      Installation. It should take less than a day to install this product if you have moderate to expert level mechanical skills, with a hard degree of difficulty.

      Application. The Kooks 1-3/4 Inch Long Tube Catted Headers are compatible with the 2015-2020 Ford Mustang GT.

      Fitment: 2015 2016 2017 2018 2019 2020

      MPN# 1151H221

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (2)

      Write a Review

      Ratings Summary

      5.0 out of 5 overall rating from 2 customers

      Installation Time: Full Day

      • February 11, 2019

        5 2017 GT - ClintY

        415 whp

        With just these, an xpipe, a very mild tune,no cat back yet, did 417 whp in TX summer heat (HPP Racing in Lewisville tx dyno)With a Lund tune, gt350 intake mani, bigger injectors, cat back (mbrp street 3”) and Pmas cai, car rips and roars. No dyno yet, but the butt dyno reads bout bout 30 to 50 more hp. Mine shop installed, also by HPP, hit them up, great shop. They are legit just google them

        Helpful (6)
      • July 25, 2018

        5 2017 GT - dg11j Installation Time: Full Day


        Sounds great, couldn't be happier with his product from AM. Would recommend to buy these if you are interested in headers.

        Helpful (8)

      Questions & Answers (5 answers)

      5 Top Rated Questions

      Will these headers direct fit to AWE Touring Edition Cat-Back? I'm thinking I want to stay NA so 1-3/4" is probably best. I have CP-E Ice box CAI SCT GTX tuner.

      • These will be a direct fit with the factory cat-back, and any cat-back exhaust that is a direct fit with the factory headers due to the step-down flanges on these headers.

      Helpful (1)

      Can you drive after these are installed until you’re able to get the car tuned?

      • No, the vehicle cannot be driven with these installed without a custom tune.

      Helpful (0)

      Will I need extensions for my O2 sensors?.

      Are you required a tune for this product?

      • Yes, a tune is required when upgrading to long tube headers.

      Helpful (0)

      The setup I would like with these headers would be with the Ford Performance Power Pack 2 and the Ford Performance by Borla cat-back exhaust. Would the tune that comes with the Power Pack be sufficient with these headers?

      • Unfortunately, the tune would not be sufficient enough for these headers and you would need to get your Mustang retuned.

      Helpful (0)
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      Installation & What's in the Box

      Installation Info

      What's in the Box

      • Long Tube Catted Headers
      • Mounting Hardware