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Kooks 1-7/8" x 3" Long Tube Headers with Catted Connection Pipes for 2012+ Jeep Grand Cherokee SRT8 & Dodge Durango SRT 6.4L HEMI
The Kooks 3410H421 1-7/8-inch long tube headers and catted connection pipes kit provides a complete bolt-on exhaust upgrade for 2012+ Jeep Grand Cherokee SRT8 and 2018+ Dodge Durango SRT models with the 6.4L HEMI V8, replacing factory manifolds to deliver dyno-verified gains of 40-50 rear-wheel horsepower and 35-45 lb-ft of torque through improved exhaust scavenging and reduced backpressure.
Handcrafted from T304 aircraft-quality stainless steel with equal-length primaries, merged collectors, and high-flow catted 3-inch connection pipes that mate directly to the OEM mid-section, this system enhances throttle response across the 4,700 RPM redline while producing a deep, aggressive V8 rumble without interior drone.
The precision laser-cut 3/8-inch thick flanges and TIG-welded construction ensure leak-free sealing under high heat loads from towing, track days, or daily acceleration, supporting up to 700 HP from stock-plus tunes. For SRT owners requiring a seamless integration of performance, emissions compliance, and durability, the 3410H421 kit delivers the engineered flow path to unlock the 6.4L's full output potential in any driving condition.
Key Features
- 1-7/8-Inch Equal-Length Primaries: Mandrel-bent for uniform exhaust pulses and optimal mid-range torque delivery.
- 3-Inch Catted Connection Pipes: High-flow stainless catalytic converters with 3-inch inlet to OEM outlet for unrestricted flow.
- T304 Stainless Steel Build: 16-gauge tubing with full TIG welds for corrosion resistance and heat tolerance over 1,600°F.
- Merged Collectors: Venturi design reduces turbulence and enhances scavenging efficiency.
- Laser-Cut Flanges: 3/8-inch thick with blended ports to prevent leaks and match cylinder head contours.
- Dyno-Tested Performance: 40-50 RWHP and 35-45 RWTQ gains on stock 6.4L engines.
Product Notes
- 49-state EPA compliant not legal for use in California or CARB-adopting states without exemption.
- Fits RWD models only excludes AWD variants due to driveline interference.
- O2 sensor extensions included professional tuning recommended for maximum gains and to avoid CEL.
- California Proposition 65: Contains chemicals known to the State of California to cause cancer or reproductive harm.
Warranty: Limited lifetime on headers and construction 25,000 miles on catalytic converters.
Installation Notes
- Professional installation advised requires lift for underbody access and alignment.
- Remove factory manifolds and heat shields torque header bolts to 25-30 ft-lbs in sequence.
- Bolt connection pipes to headers and OEM exhaust using provided gaskets and clamps.
- Complete ECU drive cycle post-install to adapt O2 sensors; recheck torque after 100 miles.
This Part Fits
| Year | Make | Model | Submodel/Engine |
|---|---|---|---|
| 2012 and 2021 | Jeep | Grand Cherokee | SRT8 and 6.4L HEMI V8 (392) |
| 2018 and 2023 | Dodge | Durango | SRT and 6.4L HEMI V8 (392) |
Note: Fits WK2 platform RWD configurations with factory exhaust routing. Verify no aftermarket modifications affect clearance.
What's Included in the Purchase
- (2) 1-7/8" x 3" Long-Tube Stainless Steel Headers with Merged Collectors
- (1) Pair of 3-Inch Inlet x OEM Outlet Catted Stainless Steel Connection Pipes
- Gaskets, Stage 8 Locking Header Bolts, and Flange Hardware
- O2 Sensor Extension Harnesses (2 x 18-inch, 2 x 6-inch)
- Exhaust Clamps and Hanger Kit
- Installation Instructions with Torque Specifications
Why Choose Kooks?
- Over 60 years of exhaust engineering, with hundreds of NHRA, NASCAR, and SCCA championships.
- Handcrafted in the USA from T304 aircraft-quality stainless steel for precision fitment.
- Limited lifetime warranty and dyno-proven designs for consistent results.
Frequently Asked Questions
-
Q: Is this kit compatible with AWD models?
A: No, designed for RWD only AWD requires custom clearance solutions. -
Q: Will it trigger a check engine light?
A: No, with included O2 extensions and proper installation tune advised for tuned setups. -
Q: What power gains can I expect on a stock 6.4L SRT?
A: 40-50 RWHP and 35-45 RWTQ, with more from complementary mods like intake or tune. -
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
- Availability: Ships within 1-2 business days custom fabrication lead times vary.
- Total Package Weight: 62 lbs | Shipping Dimensions: 48" L x 22" W x 16" H.
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