Kooks 97-04 Chevrolet Corvette Base 1-7/8 x 3 Header & Catted X-Pipe Kit

Unlock 30 to 50 Rear-Wheel Horsepower from Your C5 Corvette LS1 or LS6 with a Complete Long Tube Header and Catted X-Pipe System

The Kooks 2150H420 is a complete 1-7/8 inch x 3 inch long tube header and catted X-pipe kit engineered specifically for the 1997 through 2004 Chevrolet Corvette C5 with the LS1 5.7L V8 and the 2001 through 2004 Corvette Z06 with the LS6 5.7L V8. MPN 2150H420 replaces the factory exhaust manifolds and OEM mid-section with a hand-ported, equal-length T304 stainless steel long tube system that connects directly to the factory 2.5 inch OEM-style catback exhaust without modification. Built to order at Kooks' USA facility, the 2150H420 uses 16-gauge T304 stainless throughout, 3/8 inch laser-cut flanges, and race-specification high-flow catalytic converters in the 3 inch X-pipe for maximum scavenging and off-road competition performance.

The Kooks 2150H420 is intended for off-road and competition use only. The race catalytic converters in this kit are NOT Kooks Ultra-Green high-efficiency cats, are NOT 49-state EPA compliant, and are NOT CARB approved. This system cannot be legally installed on vehicles operated on public roads in California or other CARB-regulated states. If you require a street-legal version, refer to the 2150H410 or consult Kooks directly for a GREEN cat X-pipe option. The 2150H420 is the ideal choice for track-day builds, dedicated race Corvettes, and high-horsepower LS1 or LS6 platforms where emissions compliance is not required.

Key Features

• 1-7/8 Inch Equal-Length Primary Tubes: Mandrel-bent T304 stainless primaries balanced for broad torque delivery from 2,500 RPM through redline on the LS1 and LS6.
• 3 Inch Catted Stainless X-Pipe: Race-specification high-flow catalytic converters in a 3 inch X-pipe merge for maximum mid-range and top-end power on competition builds.
• Connects to 2.5 Inch OEM Catback: Direct bolt-on fitment to the factory Corvette catback system, no adapters or cutting required.
• Hand-Ported LS1 and LS6 Inlets: Kooks hand-ports every flange inlet to match the LS1 and LS6 cylinder head exhaust port dimensions for zero flow restriction at the source.
• 3/8 Inch Laser-Cut Flanges: Precision flanges eliminate gasket blowout and maintain a leak-free seal at the cylinder head through thermal cycling.
• 16-Gauge T304 Stainless Steel Construction: Aircraft-quality stainless with full TIG welds resists corrosion and withstands sustained exhaust temperatures above 1,500 degrees F.
• Stage 8 Locking Bolts Included: Anti-loosening header bolts prevent backing out under the vibration and thermal expansion cycles of performance driving.
• Off-Road and Competition Use: Race cats deliver unrestricted flow for track builds targeting beyond 500 horsepower with camshaft, forced induction, or nitrous upgrades.
• Handcrafted in the USA: Every Kooks 2150H420 unit is built to order at the Kooks American facility with race-proven quality control standards.

What's Included

• 2 x 1-7/8 inch x 3 inch Long Tube T304 Stainless Steel Headers with Merged Collectors, Hand-Ported LS1 and LS6 Inlets
• 3 inch x 3 inch Catted Stainless Steel X-Pipe with Race High-Flow Catalytic Converters
• Stage 8 Locking Header Bolts and Mounting Hardware
• Exhaust Gaskets
• O2 Sensor Extensions and Retainers
• Clamps
• Installation Instructions with Torque Specifications

Product Specifications

This Part Fits

Frequently Asked Questions

Q: Will the Kooks 2150H420 fit my 1997 Corvette with the LS1?
A: Yes. The 2150H420 is designed to fit all 1997 through 2004 C5 Corvette applications with the LS1 5.7L V8, including the 1997 model year. The hand-ported flanges are matched to both the early and late LS1 exhaust port dimensions.

Q: What is the difference between the 2150H420 and the 2150H430?
A: The 2150H420 uses standard race high-flow catalytic converters and is intended for off-road and competition use only. The 2150H430 is the GREEN cat version using Kooks Ultra-Green high-efficiency converters and is 49-state EPA compliant for street use. Neither version is CARB approved for California.

Q: Does the Kooks 2150H420 connect to the factory Corvette catback exhaust?
A: Yes. The X-pipe on the 2150H420 is designed to connect to the factory 2.5 inch OEM-style Corvette catback system without any modification, cutting, or adapters. The system can also be paired with an aftermarket 2.5 inch or 3 inch catback.

Q: Do I need a tune after installing the Kooks 2150H420 on my C5 Corvette?
A: A professional ECU tune is not required for the vehicle to run, but it is strongly recommended to maximize power gains and optimize air-fuel ratios for the improved exhaust flow. A tune is especially important on LS6 Z06 builds targeting maximum track performance.

Q: Is the Kooks 2150H420 legal for street use?
A: No. The 2150H420 is for off-road and competition use only. The race catalytic converters in this kit are not 49-state EPA compliant and are not CARB approved. This part is not legal for installation on vehicles driven on public roads.

Q: Will the 2150H420 work on a C5 Corvette Z06 with the LS6?
A: Yes. The 2150H420 is fully compatible with the 2001 through 2004 Corvette Z06 equipped with the LS6 5.7L V8. Kooks hand-ports the flanges to fit the LS6 exhaust port profile, and the X-pipe geometry accommodates the Z06 underbody layout.

Q: How long does it take to receive the Kooks 2150H420?
A: Each 2150H420 is built to order at the Kooks USA facility. Standard lead time is 4 to 6 weeks, with some orders extending to 8 weeks during peak production periods. Contact us before ordering if you have a firm event deadline.

Q: What is the warranty on the Kooks 2150H420?
A: Kooks provides a limited lifetime warranty on all stainless steel components to the original purchaser and a 25,000-mile warranty on the catalytic converters. Race or competition use may affect catalyst warranty coverage. review the Kooks warranty terms for full details.

Q: Does the 2150H420 require drilling, welding, or cutting for installation?
A: No drilling, welding, or cutting is required for a standard installation on a 1997 to 2004 C5 Corvette with the OEM catback exhaust. The kit includes all hardware needed for a complete bolt-on installation, including Stage 8 locking bolts, gaskets, O2 sensor extensions, and clamps.

Q: How much horsepower can I expect from the Kooks 2150H420 on my LS1 or LS6?
A: Documented dyno results on stock and mildly modified LS1 and LS6 C5 Corvettes show gains of 25 to 45 rear-wheel horsepower and 20 to 35 lb-ft of torque over factory exhaust manifolds, with the largest gains appearing in the mid-range and upper RPM range. Results vary with tune, supporting modifications, and vehicle condition.

Prop 65 Warning

California Proposition 65 Warning: This product can expose you to chemicals including Chromium and Nickel, which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Installation Instructions

1. Raise the vehicle on a lift or secure jack stands and allow the factory exhaust system to cool completely before beginning disassembly.
2. Disconnect the negative battery terminal to prevent accidental O2 sensor or PCM damage during removal.
3. Remove the factory exhaust manifolds by unbolting the header-to-head fasteners, then disconnect and set aside the OEM O2 sensors and catalytic converter assembly.
4. Clean the cylinder head exhaust ports and inspect the sealing surfaces for cracks or warping before installation.
5. Install the supplied exhaust gaskets onto the cylinder head exhaust ports, then position the Kooks 2150H420 long tube headers and hand-thread the Stage 8 locking bolts to verify alignment before final torque.
6. Torque the header flange bolts in a cross pattern to the specification provided in the Kooks installation manual, typically 18 to 22 ft-lb for LS applications.
7. Install the 3 inch catted X-pipe, connecting the X-pipe inlet flanges to the header collectors and the X-pipe outlets to the factory 2.5 inch OEM catback. Tighten all clamps evenly.
8. Route and install the included O2 sensor extensions, plugging the existing O2 sensor connectors into the extensions and threading the sensors into the new X-pipe bungs.
9. Reconnect the negative battery terminal, start the engine, and inspect all flange and clamp connections for exhaust leaks. Retorque fasteners after the first heat cycle.
10. A professional ECU tune is strongly recommended after installation to optimize air-fuel ratios and timing for maximum power gains.