The factory exhaust manifolds on your Mustang GT are one of the first restrictions holding back your 5.0L Coyote. Speed Engineering's 1-7/8" longtube headers are a direct-fit, dyno-proven upgrade — mandrel bent, TIG-welded, and CNC-machined from 304 natural stainless steel with merge spikes and port-matched flanges for maximum exhaust flow and over 25 rear-wheel horsepower over stock. X-pipe sold separately.
⚠️ Important Notes:
- Header Bolt Thread Pitch:
- Early Gen 1 (2011) and some Gen 3 (2018+): M10x1.25
- Late Gen 1 (2011) and Gen 2 (2015–2017): M10x1.5
- Verify your thread pitch before ordering bolts
- O₂ Sensor Extensions Required — Select the correct harness for your model year:
- 2011–2014 Mustang GT: 6-pin O₂ extension (Speed Engineering 31-1038)
- 2015–2017 Mustang GT: square 6-pin O₂ extension (Speed Engineering 31-1008)
- 2018–2023 Mustang GT: flat 5-pin O₂ extension (Speed Engineering 31-1009)
Features:
- Full 1-7/8" Port-Matched Primary Tubes with Merge Spikes — Maximum flow from cylinder head to collector for aggressive Coyote performance
- 3" Collector — Optimized for strong low-to-mid RPM torque
- Mandrel Bent Tubing — Consistent tube diameter through every bend; no crimping, no restriction
- CNC Machined Flanges — Precision fit at the head and collector for a leak-free seal
- 304 Natural Stainless Steel Construction — Corrosion resistant, heat tolerant, and built to last
- Longtube Header Design — Maximum scavenging efficiency vs. shorty or mid-length headers
- Standard Graphite Manifold Gaskets Included
- Dyno Proven — 25+ RWHP gain on 5.0L Coyote applications
- Compatible with 5.0L Coyote V8 Engines
- V8 Engines Only
Vehicle Applications:
Ford Mustang GT — 5.0L Coyote (RWD)
- 2011 Ford Mustang GT (RWD) — 5.0L Coyote Gen 1
- 2012 Ford Mustang GT (RWD) — 5.0L Coyote Gen 1
- 2013 Ford Mustang GT (RWD) — 5.0L Coyote Gen 1
- 2014 Ford Mustang GT (RWD) — 5.0L Coyote Gen 1
- 2015 Ford Mustang GT (RWD) — 5.0L Coyote Gen 2
- 2016 Ford Mustang GT (RWD) — 5.0L Coyote Gen 2
- 2017 Ford Mustang GT (RWD) — 5.0L Coyote Gen 2
- 2018 Ford Mustang GT (RWD) — 5.0L Coyote Gen 3
- 2019 Ford Mustang GT (RWD) — 5.0L Coyote Gen 3
- 2020 Ford Mustang GT (RWD) — 5.0L Coyote Gen 3
- 2021 Ford Mustang GT (RWD) — 5.0L Coyote Gen 3
- 2022 Ford Mustang GT (RWD) — 5.0L Coyote Gen 3
- 2023 Ford Mustang GT (RWD) — 5.0L Coyote Gen 3
Frequently Asked Questions:
Q: Is an X-pipe included with these headers? No. These are headers only. The Speed Engineering X-pipe kit for the 2011–2023 Mustang GT is sold separately and is required to connect the headers to your cat-back exhaust system.
Q: What O₂ sensor extensions do I need? O₂ sensor extensions are required. Select based on your model year: 2011–2014 Mustang GT uses the 6-pin extension (Speed Engineering 31-1038); 2015–2017 uses the square 6-pin extension (Speed Engineering 31-1008); 2018–2023 uses the flat 5-pin extension (Speed Engineering 31-1009).
Q: What header bolt thread pitch do I need? Early Gen 1 (2011) and some Gen 3 (2018+) Coyote engines use M10x1.25 bolts. Late Gen 1 (2011) and Gen 2 (2015–2017) use M10x1.5 bolts. Verify your thread pitch before sourcing header bolts.
Q: How much horsepower do these headers add? Speed Engineering's 1-7/8" longtube headers are dyno proven to add over 25 rear-wheel horsepower on 5.0L Coyote Mustang GT applications compared to stock exhaust manifolds.
Q: What is the difference between these headers and the full kit (25-1085)? These are headers only. The full kit includes the headers plus the Speed Engineering X-pipe, O₂ extensions, MLS gaskets, and header bolts — everything needed for a complete front-to-cat-back connection. Choose headers only if you already have or plan to source the X-pipe separately.
Q: What material are these headers made from? 304 natural stainless steel with full TIG-welded construction, CNC-machined flanges, merge spikes, and port-matched flanges.
Q: Are gaskets included? Yes. Standard graphite manifold gaskets are included with the headers.
Q: Are these headers street legal? No. These are race-only headers intended for closed-course competition use only. Installation on a street-driven vehicle may violate the Clean Air Act (42 U.S.C. 7522(a)(3)).
⚠️ Race Use Only: This product is manufactured and sold for installation on vehicles used solely for competition. Once installed, the vehicle may not be used, registered, or licensed for use on a public road or highway. Installation on a street-driven vehicle may violate the Clean Air Act 203(a)(3), 42 U.S.C. 7522(a)(3).
