Kooks 1-7/8" Header and Catted Conn. 2011-2014 Mustang GT 5.0L 4V.

Kooks 1-7/8" x 3" Long Tube Headers & GREEN Catted X-Pipe for 2011–2014 Ford Mustang GT 5.0L Coyote

The Kooks 1141H450 1-7/8-inch long tube headers and GREEN catted X-pipe kit delivers the complete bolt-on exhaust upgrade for 2011–2014 Ford Mustang GT models with the 5.0L Coyote V8, replacing factory manifolds to unlock dyno-proven gains of 55–70 rear-wheel horsepower and 50–65 lb-ft of torque through equal-length primaries, merged collectors, and a high-flow 3-inch x 3-inch x 2-1/2-inch OEM GREEN catted X-pipe that connects directly to the factory exhaust for seamless integration and unrestricted flow from idle to redline.

Handcrafted from T304 aircraft-quality stainless steel with 3/8-inch laser-cut flanges, full TIG welds, and 400-cell metallic substrate GREEN catalytic converters, this system supports over 850 HP while remaining 49-state emissions compliant and preserving the Mustang GT's aggressive V8 soundtrack without drone. The precision design maintains factory ground clearance and heat shielding for daily-driven performance cars.

For 5th-gen Mustang GT owners who demand championship-level performance with street-legal reliability, the 1141H450 kit is the race-winning, complete bolt-on solution trusted by Coyote enthusiasts worldwide.

Key Features

• 1-7/8-inch equal-length mandrel-bent primaries for maximum scavenging
• 3-inch x 3-inch x 2-1/2-inch OEM GREEN high-flow metallic catalytic converters
• Full T304 stainless steel with TIG welds and 3/8-inch flanges
• Merged collectors for optimal exhaust velocity
• Direct bolt-on to OEM exhaust no cutting required
• Dyno gains of 55–70 RWHP and 50–65 RWTQ

Product Notes

• 49-state EPA compliant not for sale or use in California or CARB states without exemption
• Fits 2011–2014 Mustang GT coupe and convertible with 5.0L Coyote
• Includes O2 extensions and all necessary hardware

California Proposition 65: Contains chemicals known to the State of California to cause cancer or reproductive harm.

Warranty: Limited lifetime on stainless construction and 25,000 miles on catalytic converters to original purchaser.

Installation Notes

• Professional installation required lift and exhaust experience needed
• Remove factory manifolds and bolt headers to cylinder heads
• Connect catted X-pipe to collectors and OEM mid-pipe
• Torque flanges to 25-30 ft-lbs and run drive cycle for ECU adaptation

This Part Fits

Note: Fits all 2011–2014 Mustang GT coupe and convertible with factory exhaust. Manual or automatic.

What's Included in the Purchase

• (2) 1-7/8" x 3" Long-Tube T304 Stainless Headers with Merged Collectors
• (1) 3" x 3" x 2-1/2" OEM GREEN Catted Stainless X-Pipe
• Gaskets, Stage 8 Locking Bolts, Clamps and Hardware
• O2 Sensor Extensions
• Detailed Installation Instructions
• Part Number: Kooks 1141H450

Why Choose Kooks?

• Over 60 years of championship-winning exhaust engineering
• Handcrafted in the USA from T304 aircraft-quality stainless steel
• Limited lifetime warranty and dyno-proven performance

Frequently Asked Questions

• Q: Does this fit my 2013 Mustang GT?
  A: Yes, direct bolt-on for all 2011–2014 Mustang GT
• Q: Will it cause a check engine light?
  A: No, GREEN cats and extensions maintain proper O2 function
• Q: How loud is it?
  A: Aggressive V8 roar at WOT, refined and drone-free at cruise

Shipping & Handling

• Method: UPS or Fed Ex Ground.
• Availability: Typically ships same day or next if in stock.
• Packaging: Heavy-duty box with foam protection.