Kooks 3610H421 1-7/8 x 3 Long Tube Headers and Catted Connection Kit 2011-2023 Jeep Grand Cherokee 2011-2024 Dodge Durango 5.7L HEMI

Unlock HEMI Breathing Potential in Your Grand Cherokee or Durango

The Kooks 3610H421 long tube header and catted connection kit is built specifically for the 2011 through 2024 Jeep Grand Cherokee and Dodge Durango equipped with the 5.7L HEMI V8. Kooks fabricates each primary tube from mandrel bent T304 stainless steel at 1-7/8 inches, flowing into a 3-inch collector and matching 3-inch connection pipes with integrated 400-cell metallic high-flow catalytic converters. Every component is TIG welded and hand finished at Kooks' Statesville, North Carolina facility, and the kit ships complete with exhaust gaskets, O2 sensor extension harnesses, clamps, and all required mounting hardware.

The 3610H421 covers both WK2 generation Grand Cherokees from 2011 through 2021 and the WL generation from 2022 onward, as well as the Durango through the 2024 model year. The 3/8-inch laser cut flanges seal against the 5.7L HEMI cylinder head ports without distortion, and the primary tube geometry is engineered to clear the factory suspension, steering, and frame components without modification. Kooks backs this system with a limited lifetime warranty to the original purchaser.

Key Features

• 1-7/8-inch mandrel bent T304 stainless primary tubes for peak exhaust scavenging
• 3-inch collector diameter with matching 3-inch catted connection pipes
• 400-cell metallic high-flow catalytic converters in the connection pipes
• 3/8-inch laser cut flanges for a leak-free seal at the HEMI cylinder head
• Fits WK2 (2011 to 2021) and WL (2022 to 2023) Grand Cherokee generations
• Covers Dodge Durango 5.7L HEMI 2011 through 2024
• TIG welded and hand finished in Statesville, NC USA
• Includes gaskets, O2 extensions, clamps, and all hardware
• Limited lifetime warranty to original purchaser
• Not CARB legal, not for street use in California

What's Included

• 1-7/8-inch x 3-inch T304 stainless long tube header set (driver and passenger)
• 3-inch catted stainless connection pipes with 400-cell metallic high-flow catalytic converters
• OEM-outlet transition pipes
• Exhaust gaskets (full set)
• O2 sensor extension harnesses
• Header bolts, clamps, and all required mounting hardware

Fitment

Specs

Frequently Asked Questions

• Does the Kooks 3610H421 fit the 2020 Jeep Grand Cherokee 5.7L HEMI?
  Yes. The 3610H421 fits all 2011 through 2023 Jeep Grand Cherokee models with the 5.7L HEMI, covering both the WK2 generation (2011 to 2021) and the WL generation (2022 to 2023). It also fits the Grand Cherokee L from 2021 to 2022.
• Does the 3610H421 fit the Dodge Durango 5.7L HEMI?
  Yes. This kit covers 2011 through 2024 Dodge Durango models with the 5.7L HEMI V8 across all trim levels including R/T, GT, Citadel, Limited, and SXT.
• Does this kit include catalytic converters?
  Yes. The included connection pipes contain 400-cell metallic high-flow catalytic converters. This kit is designed for off-road and track use and is not CARB certified.
• Is the Kooks 3610H421 legal for street use in California?
  No. This system is not CARB certified and is not legal for street use in California. It is intended for off-road and competition use only.
• Will I need a tune after installing these headers?
  A professional ECU tune is strongly recommended. Long tube headers on the 5.7L HEMI will typically trigger O2 sensor codes and benefit from a custom tune to maximize power gains and drivability.
• Does this kit require any drilling or cutting?
  No. The 3610H421 is a direct bolt-on design using the factory mounting locations on both the Grand Cherokee and Durango platforms without modification.
• What is the warranty on Kooks headers?
  Kooks provides a limited lifetime warranty to the original purchaser covering defects in materials and workmanship. The Magnuson-Moss Warranty Act protects your right to use aftermarket parts without voiding your vehicle warranty for unrelated components.
• Does this fit the 6.4L HEMI Grand Cherokee SRT?
  No. The 3610H421 is designed specifically for the 5.7L HEMI. The 6.4L SRT and Trackhawk use different port geometry and require a separate Kooks part number.
• Does the 3610H421 work with the stock cat-back?
  Yes. The connection pipe transitions to the factory outlet diameter so the system connects directly to the OEM cat-back or any aftermarket cat-back sized to the OEM outlet specification.

Installation Instructions

Professional installation is strongly recommended. Raise and secure the vehicle on a lift or jack stands and allow all exhaust components to cool completely. Disconnect the negative battery terminal. Remove the factory exhaust manifolds, Y-pipe, and catalytic converters. Clean all cylinder head mating surfaces. Install the supplied exhaust gaskets and position the headers, torquing the flange bolts to the manufacturer specification using the included hardware. Route the catted connection pipes and confirm clearance from the steering, suspension, and frame. Connect the O2 sensor extension harnesses and torque all clamps to spec. Reconnect the battery and perform an ECU reset or schedule a professional tune. Inspect all connections for leaks after the first heat cycle and re-torque as needed.

Prop 65 Warning

WARNING: This product can expose you to chemicals including chromium and nickel, which are known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.