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A complete header upgrade for your Mustang
Enjoy the character of your Coyote with a header package that includes the connections to finish the job. These Kooks kits combine long tube headers, front connection pipes and OEM adapters for the 2015-2026 Mustang GT and the 2024-2026 Dark Horse 5.0. Choose from the actual primary and catalyst combinations below, whether your plans centre on a naturally aspirated car or a more powerful forced-induction build.
SKUs: 1151H222, 1151H232, 1151H442, 1151H452, 1151H632, 1151H642, 1151H6SS
Choose the kit around your engine
The primary size and catalyst type are separate decisions. Primary diameter should suit the engine output and rev range; the catalyst needs to suit the engine power and whether it uses a supercharger or turbo. Performance Cats are for naturally aspirated engines. GREEN, H.O. GREEN and ULTRA-GREEN options support forced-induction applications within their respective ratings.
What changes between the GREEN versions
GREEN uses a 400 CPSI substrate in a 4" catalyst body. H.O. GREEN uses a 300 CPSI substrate in a larger 4-1/2" body for higher-output applications. ULTRA-GREEN uses a 400 CPSI substrate in a 4-1/2" body with additional precious-metal content. CPSI means cells per square inch: it describes the catalyst substrate, rather than a horsepower gain.
Headers, connections and fitting parts together
The 304 stainless headers have mandrel-bent primaries, 3/8" laser-cut flanges and 3" collectors with a scavenging spike. The kits include the front connections, OEM adapters, gaskets, O2 extensions, clamps and bolts for the OEM-exhaust connection. The ULTRA-GREEN kit also includes O2 spacers.
Two pipe sets with Street/Strip
The Street/Strip package includes H.O. GREEN catted front pipes and a separate set of competition-only front pipes. You can fit the catted set and retain the other pipes for a dedicated track installation. The competition pipes are not for public-road use, and this package requires a Kooks competition-use waiver.
Fitting and calibration
We recommend professional installation. Sensor leads, engine-bay clearance and the connection to your rear exhaust should be checked together, with fasteners checked after the first heat cycle.
Tuning for your header upgrade
We recommend a tune with these headers, matched to your engine and the completed exhaust. For a 2015-2017 GT 5.0, see our Mustang GT custom ECU tuning. For 2024+ cars, we have GT S650 tuning and Dark Horse tuning listings. The S650 listings cover Stage 1 tuning; contact us to discuss calibration for your header conversion before booking. For a 2018-2023 GT, Bullitt or Mach 1, get in touch to discuss tuning for your car.
Choose your option
| SKU | Header Size | Cat Type | Fitting / contents | Stated use restriction |
|---|---|---|---|---|
| 1151H222 | 1-3/4" | Performance Cats | OEM adapters; naturally aspirated application only. | Competition, off-road and track use only. Not for use on public roads. |
| 1151H232 | 1-3/4" | GREEN Cats | OEM adapters; GREEN catalysts support naturally aspirated or forced-induction applications. | |
| 1151H442 | 1-7/8" | H.O. GREEN Cats | OEM adapters; larger-body H.O. GREEN catalysts. | |
| 1151H452 | 1-7/8" | ULTRA GREEN Cats | OEM adapters and O2 spacers; larger-body ULTRA-GREEN catalysts. | |
| 1151H632 | 2" | GREEN Cats | OEM adapters; GREEN catalysts. | |
| 1151H642 | 2" | H.O. GREEN Cats | OEM adapters; larger-body H.O. GREEN catalysts. | |
| 1151H6SS | 2" | Street/Strip | Includes BOTH H.O. GREEN catted front pipes and a separate competition-only front-pipe set, plus OEM adapters. | Competition, off-road and track use only. Not for use on public roads. Kooks competition-use waiver required. |
Vehicle fitment
| Years | Vehicle and trim | Engine | Applicable SKU / fitting conditions |
|---|---|---|---|
| 2015-2026 | Ford Mustang GT | 5.0L V8 | 1151H222, 1151H232, 1151H442, 1151H452, 1151H632, 1151H642, 1151H6SS |
| 2015-2026 | Ford Mustang GT Premium | 5.0L V8 | 1151H222, 1151H232, 1151H442, 1151H452, 1151H632, 1151H642, 1151H6SS |
| 2015 | Ford Mustang GT 50 Years Limited Edition | 5.0L V8 | 1151H222, 1151H232, 1151H442, 1151H452, 1151H632, 1151H642, 1151H6SS |
| 2019-2020 | Ford Mustang Bullitt | 5.0L V8 | 1151H222, 1151H232, 1151H442, 1151H452, 1151H632, 1151H642, 1151H6SS |
| 2021-2023 | Ford Mustang Mach 1 | 5.0L V8 | 1151H222, 1151H232, 1151H442, 1151H452, 1151H632, 1151H642, 1151H6SS |
| 2024-2026 | Ford Mustang Dark Horse | 5.0L V8 | 1151H222, 1151H232, 1151H442, 1151H452, 1151H632, 1151H642, 1151H6SS |
| 2024-2026 | Ford Mustang Dark Horse Premium | 5.0L V8 | 1151H222, 1151H232, 1151H442, 1151H452, 1151H632, 1151H642, 1151H6SS |
Ordering and delivery
Estimated lead time is 4-6 weeks. Delivery may be faster depending on stock levels. Shipping is charged separately.
Technical specifications
| Specification | Details |
|---|---|
| Application | Mustang GT 5.0, 2015-2026; Dark Horse 5.0, 2024-2026 |
| Construction | 304 stainless steel; mandrel-bent primaries; 3/8" laser-cut flanges |
| Collector design | 3" collectors with scavenging spike |
| Supplied exhaust parts | Long tube header pair, front connection pipes and OEM adapters |
| Supplied fitting parts | Gaskets, O2 extensions, clamps and bolts; O2 spacers also included with ULTRA-GREEN |
| Catalyst design choices | Performance Cats; GREEN; H.O. GREEN; ULTRA-GREEN; Street/Strip with H.O. GREEN pipes plus a separate competition pipe set |
| Calibration | Hoonies recommends a tune matched to the completed header and exhaust installation |
Frequently asked questions
Does this include the headers and adapters?
Yes. These are header and front-connection packages with OEM adapters and the listed fitting parts, ready to join the compatible OEM rear exhaust.
What does Street/Strip actually supply?
It supplies the headers and OEM adapters with two front-pipe sets: H.O. GREEN catted pipes and separate competition-only pipes. The track pipes are not for public-road use.
Can I use Performance Cats with a supercharger?
No. Performance Cats are for naturally aspirated applications. Choose an appropriate GREEN-family catalyst for forced induction and match its capacity to the build.
Will a catted kit guarantee no check-engine light?
No catalyst choice guarantees the warning light will stay off. Match the hardware and calibration to the completed engine and exhaust.
Is every size available with every catalyst?
The table shows the combinations we actually offer. Choose a listed SKU rather than assuming every primary and catalyst can be combined.
