Kooks 05-10 Ford Mustang GT Manual 1 5/8in x 2 1/2in SS Long Tube Headers and OEM Catted SS X Pipe

Kooks 1-5/8" Long Tube Headers and 2-1/2" Catted X-Pipe for 2005 and 2010 Ford Mustang GT 4.6L 3V

The Kooks 1131H020 1-5/8-inch long tube headers and catted X-pipe kit provides the full bolt-on exhaust upgrade for 2005 and 2010 Ford Mustang GT models with the 4.6L 3V V8. It replaces factory manifolds to deliver dyno-proven 40 and 55 rear-wheel horsepower and 35 and 50 lb-ft of torque gains through equal-length primaries, merged collectors, and a high-flow 2-1/2-inch catted X-pipe that connects directly to the OEM exhaust.

Handcrafted from T304 stainless steel with laser-cut 3/8-inch flanges and full TIG welds, the system sharpens throttle response and adds a deep, aggressive V8 tone with no interior drone. It supports up to 600 HP while remaining 49-state emissions compliant.

Key Features

• 1-5/8-Inch Equal-Length Primaries Mandrel-bent for maximum scavenging and torque
• 2-1/2-Inch High-Flow Catted X-Pipe 400-cell metallic core rated for 600+ HP with OEM outlet
• T304 Stainless Steel Full TIG welds and 16-gauge tubing for lifetime durability
• Merged Collectors Optimized flow for broader powerband
• Direct OEM Connection Bolts straight to factory exhaust without modifications
• Dyno Gains 40 and 55 RWHP and 35 and 50 RWTQ on stock 4.6L 3V

Product Notes

• 49-state EPA compliant. Not legal in California or CARB states
• Fits manual and automatic transmissions with factory 4.6L 3V
• O2 sensor extensions included. Drive cycle required after install
• California Proposition 65 warning applies

Warranty Limited lifetime on stainless parts and 25,000 miles on catalysts

Installation Notes

• Professional installation recommended. Vehicle lift required
• Torque header bolts to 22-28 ft-lbs in stages using supplied Stage 8 hardware
• Connect X-pipe to factory section with included clamps and gaskets
• Recheck torque after first heat cycle and 100 miles

This Part Fits

Note: Fits coupe and convertible with factory 4.6L 3V. Excludes GT500 with 5.4L.

What's Included in the Purchase

• (2) 1-5/8" x 2-1/2" Long-Tube T304 Stainless Headers with Merged Collectors
• (1) 2-1/2" Catted Stainless X-Pipe with OEM Outlet
• Gaskets, Stage 8 Locking Bolts, Clamps and Hardware
• O2 Sensor Extensions
• Installation Instructions
• Part Number: Kooks 1131H020

Why Choose Kooks?

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

Frequently Asked Questions

• Q: Does this fit my 2008 Mustang GT automatic?
  A: Yes, direct bolt-on for all 2005 and 2010 GT manual and auto with 4.6L 3V
• Q: Will it cause a check engine light?
  A: No, catted X-pipe and extensions keep all sensors in correct positions
• Q: How loud is it?
  A: Deeper and louder at wide-open throttle, quiet and drone-free at cruise
• Do Kooks headers require a tune after installation?
  Yes. A professional tune is strongly recommended after installing long tube headers. The significant improvement in exhaust flow changes air fuel ratios and requires ECM recalibration to achieve optimal power output and safe operation.
• Will these headers void my factory powertrain warranty?
  Under the Magnuson-Moss Warranty Act, a manufacturer cannot void your vehicle warranty simply because you installed an aftermarket part unless they prove the component directly caused the failure. Consult your dealer for specifics on your situation.
• Q: Do these Kooks headers require a tune after installation?
  A: Yes. A professional tune is strongly recommended after installing long tube headers. The significant improvement in exhaust flow changes air fuel ratios and requires ECM recalibration to achieve optimal power output and safe operation.
• Q: Will Kooks headers void my factory powertrain warranty?
  A: Under the Magnuson-Moss Warranty Act, a manufacturer cannot void your vehicle warranty simply because you installed an aftermarket part unless they prove the component directly caused the failure in question. Consult your dealer for specifics.
• Q: What warranty does Kooks provide?
  A: Kooks products are backed by a limited lifetime warranty to the original purchaser against defects in materials and workmanship. Racing and competition use applications may have specific warranty exclusions. Contact Kooks Performance directly for warranty details.

Shipping & Handling

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