FREE 2 or 3-Day Delivery on 10,000+ Items. Details

Talk to a Mustang Enthusiast
M-F 8:30A-11P, Sat-Sun 8:30A-9P
Win $3,000 in Store Credit! Enter Daily >

Kooks 1-3/4-Inch Long Tube Headers (11-14 Mustang GT)

Item 65503
AmericanMuscle no longer carries the Kooks 1-3/4-Inch Long Tube Headers (11-14 Mustang GT). Please check out 2015-2022 Mustang Headers for an updated selection.
Call a Mustang Enthusiast at 1-877-887-1105
M-F 8:30A-11P, Sat-Sun 8:30A-9P

    Video Review & Installation

    Justin: So the Kooks one and three-quarter inch long tube headers here should appeal to the 2011 through '14 GT owners out there who are looking to grab one of the nicest long tubes in the category from a construction and build standpoint, and would prefer that slightly smaller one and three-quarter inch primary to the larger one and seven-eights inch header. Now, the Kooks headers here will not include a shorty mid-pipe right out of the box, so interested buyers will need to also pick up a corresponding Kooks X or H-pipe on the site to complete the overall package. Now, by themselves, the headers will run you right around 1,000 bucks and the install will get a knuckle-busting three out of three wrenches on the difficulty meter, and we will have a detailed walk-through to come later in the video. Now, for the guys out there who might not be aware, Kooks makes an absolutely killer header, and a killer product overall. In fact, I've had the pleasure of touring the Kooks facilities, and I can say the gang down there in North Carolina take a lot of pride in their work because it really does show in the final product as is the case here with this Coyote header. But why go with an aftermarket long tube header in the first place? Well, simple, right? To get more power and more sound out of your naturally aspirated or blown Coyote engine. Now, we are gonna show you guys some dyno numbers here. The car we're using does have some existing modifications like a Boss manifold and a custom tune, so we established a baseline run first, then got to work installing the Kooks long tube headers in addition to a catted X-pipe, re-ran the car and here are those results. Baseline run using our manual S197 GT gave us 398 horse power and 347 pound feet of torque at the rear wheels. With the Kooks long tubes in place, the car is now making 406 horse power and 349 pound feet of torque to the rear wheels. That's good for a peak gain of 8 horse power over those baseline numbers, and gains of as much as 18 horse power and 16 pound feet of torque under the curve. But power aside, another big draw with adding a long tube like this is just the total transformation of your exhaust tone and also your volume. Just a downright angry tone with a lot more bark is the best way I can sum it up. Now, ultimately, again, you're gonna have a few different things to help shape your sound, whether it be your mid-pipe, X or H, catless versus catted, in addition to the exhaust itself. But either way, just know that things are gonna be noticeably louder with a long tube in place. But let's get back to the Kooks headers we're talking about here in this video, and again, guys, just superb quality from the gang over at Kooks. This does include the premium 304-grade stainless steel throughout your mandrel bent one and three-quarter inch primaries, three-eights inch laser-cut flange at the head, all ending in your 3 inch collectors down here, of course loaded with Kooks' merge spike technology. And that's just basically designed to help increase exhaust velocity, scavenging, things like that, making for better flow overall. And on top of that, guys, just beautiful construction, quality welds, all the welds at the head have been smoothed out to help reduce that turbulence and just make for a better product overall. Let's touch on that one and three-quarter inch primary size a little bit more. Again, one of your most common diameters here in the Coyote aftermarket, along with that slightly larger one and seven-eights inch offering. And look, guys, they're both gonna make power over the factory manifolds you are replacing, but conventional wisdom might tell you, a smaller diameter primary will make slightly better torque at lower rpm levels but be more of a restriction at the upper rpm level when you're making bigger power and vice versa. So, what I will say the difference is going to be extremely minimal on most setups here, however, if you guys are leaning towards forced induction in the long road, I might steer you more towards that slightly larger primary like the one and seven-eights inch option for instance, but again, both will certainly make more power over those factory manifolds. Now, speaking of making more power, ideally I'd recommend pairing a long tube with a custom tune, not only to maximize your gains, but, if you do decide to go with an off-road or catless mid-pipe, it will address the secondary O2s on your ride. I do wanna remind you guys that the Kooks long tube headers, again, do not include a mid-pipe, meaning you're gonna need to purchase one separately in order to connect the long tubes to either your stock or aftermarket exhaust system. And I do wanna point out that Kooks offers a number of different mid-pipe solutions here on the site, it's one of the things I really dig about the company, including X and H-pipe variations, catless or off-road versions, obviously catted stuff as well, and even their green cat option, which is an EPA certified high flow cat. And those guys will often times owing the EPA emissions issues, and also some inefficiency codes as well that can sometimes come along with other high flow cat options. So, either way, guys, feel free to check out the many different mid-pipe solutions from Kooks, again, about six altogether, here at AM if you haven't already done so. Let's shift gears and talk about the installation, and honestly, guys, there's no sugarcoating this one, long tube headers on an S197 are not fun, so expect a full three out of three wrenches on the difficulty meter, and at least a day or two in the shop or garage to get this one knocked out. And to give you a better idea of what you're in for with this job, here's a detailed walk-through and a tool breakdown. Man: The first thing we're gonna do is remove the engine service cover, we got three 8 millimeter bolts. And after that we're gonna remove the K-member brace, that's gonna open up some room for us. All right. Next, with a 15 millimeter ratchet wrench we're gonna remove the chassis support brace here, there's four nuts. Next thing we're gonna do is remove the upper motor mount nuts, I got a 15 millimeter socket here and a long extension. I'm using a magnet to retrieve the fallen nut. We're now ready to remove our motor mounts. I have a 13 millimeter socket, I also am using a pole jack right here. Once we get our motor mounts loose, we're gonna lift the engine up three to four inches, and that's gonna give us some more room to remove our stock manifolds. You can now pull the right side motor mount out of the car. Lift the engine up slightly to get this guy out. Okay, we're gonna do the same thing on the left side now. Now we're ready to remove the stock manifolds. I have a 15 millimeter on a small extension, I'm gonna be switching up tools here, some of them are easier to get to, some of them are harder to get to. I went through and broke a couple loose, I'm gonna use a power ratchet to speed things up a little bit. Before we remove our manifold, we need to unclip the O2 sensor. Now we're ready to pull the stock header out of the car. We're gonna move on to the left side of the car now. First thing we're gonna do is disconnect our steering shaft and move that out of the way. From there we can start loosening up the manifold nuts. We're gonna take a Sharpie and put a straight line down the center of steering shaft so when we go to put it back together we can have it in the right orientation. All right, we've got all our nuts off of the stock manifold. I unclipped our O2 sensor, and now we can pull the stock manifold out. After that, we can begin to install our new Kooks headers. We are now ready to install our new long tube headers. We're gonna slide the long tubes up in place and get some nuts started on them. All right, we're now gonna install the right side long tube. Once all your bolts are tightened on your new long tubes, you can then reinstall your motor mounts. Okay, next, we can reconnect our steering shaft. Next thing we can do is put the right side motor mount back in place. I'm gonna lower the engine back down now. Once we get it all the way down we can get the nut started on the top of the motor mount, but we won't be able to tighten them up until the car is on the ground and we can get through it from the engine bay. We're gonna put our starter back in place now. All right. One of the last things we're gonna do under here is put our O2 sensors back in. I chose to do it somewhat last, you guys can put these in before you install your X-pipe or your headers, it's all up to you. All right. And now we're gonna plug it in. All right. We got a few things to wrap up here. This is the K-member support bar that can go back on. After this, we can put our K-member support brace back up, and that's gonna wrap things up. Yep. And we're using a 15 millimeter socket here to tighten these down. All right, guys, that's gonna wrap up our review and install. Be sure to check out more at

    Product Information

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


    • Increases RWHP and Torque
    • Long Tube Header Design
    • Free Flowing 1-3/4" Mandrel-Bent Tubing
    • 304 Stainless Steel Construction
    • TIG Welded for Strength
    • Fits 2011-2014 GT Mustangs


    More Horsepower and Torque. A set of Kooks Long Tube Headers will greatly improve the performance of your 5.0L Coyote Mustang. Kooks Headers feature an integrated venturi style collector that increases exhaust scavenging, and reduces turbulence to improve your 5.0's exhaust flow over the restrictive stock manifolds, boosting your Pony's horsepower and torque numbers.

    Quality Construction. Kooks Long Tube Exhaust headers are manufactured from 1-3/4" mandrel bent 304 stainless steel tubing for superior airflow. These headers are TIG welded and feature a leak-free ball flange design for optimal performance and a better than OEM fit. Stainless steel hardware and gaskets are included.

    Recommended Upgrade. To realize the full power potential that these Long Tube Headers have to offer, AmericanMuscle recommends a custom tune with a Mustang Handheld Tuner to reprogram the vehicles computer (ECU) for proper operation.

    Application. These Kooks Long Tube Headers are designed to fit the 2011-2014 5.0L GT Mustangs. Kooks long tube headers require the use of a Kooks shorty midpipe in order to be installed properly (see drop down option above).

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

    CA Residents: WARNING: Cancer and Reproductive Harm -

    Installation & What's in the Box

    Installation Info

    What's in the Box

    • (1) Driver side header
    • (1) Passenger side header
    • (2) Gaskets
    • (16) Flange bolts
    • (4) Bolts
    • (4) Nuts
    • (8) Flat washers

    Tech Specs

    Header Specifications
    Header Type: Long Tube Finish : Natural
    Type Mid Pipe Required: Shorty Fitment: 2011-2014 5.0 GT Mustangs

    Customer Reviews (39)

      Questions & Answers

      10 More Questions