Speed Engineering 1-7/8" Longtube Headers — 2011–2023 Ford Mustang GT | 5.0L Coyote | 25-1085

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

FAQ

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.

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).

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.

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.

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.

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.

Are gaskets included?

Yes. Standard graphite manifold gaskets are included with the headers.

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).