How to Install Long-Tube Headers on a C6 Corvette (05-13)

Installing long-tube headers on a C6 Corvette is the single most effective bolt-on for waking up the LS engine — a well-matched header, high-flow connection pipe, and tune can add roughly 15 to 25 rear-wheel horsepower and torque on a naturally aspirated LS3, plus a deeper, race-bred exhaust note. The catch is that the job replaces the factory cast exhaust manifolds and connection pipe, so it demands the right kit for your year and engine, new gaskets, careful torque, and a follow-up tune. This step-by-step guide walks through exactly how to install long-tube headers on a 2005–2013 C6 Corvette, which Kooks kit fits your car, and the specs that matter. At NLP Performance in Tampa, FL, these Kooks header kits are among our most-asked-about LS upgrades.

What Do Long-Tube Headers Do for a C6 Corvette?

Long-tube headers are a set of tubular stainless exhaust manifolds that replace the restrictive factory cast manifolds on your C6 Corvette, using individual equal-length primary tubes that merge into a single 3 in collector to scavenge exhaust gas and reduce backpressure. On the LS platform — the 6.0L LS2, 6.2L LS3, 7.0L LS7, and supercharged 6.2L LS9 — this is the highest-return exhaust modification you can make. In our experience, a naturally aspirated C6 running long-tube headers, a high-flow catted connection pipe, and a proper tune typically nets around 15 to 25 rear-wheel horsepower and a similar torque figure, with the biggest gains arriving from 3,500 rpm to redline.

Just as important is what you can feel and hear. The C6 gains a noticeably harder mid-range pull and the unmistakable LS long-tube rasp on throttle. Kooks builds the C6 kits from 304 stainless steel with CNC-machined flanges for a leak-free seal, and the GREEN Connection catted pipes retain high-flow catalytic converters so the car stays street-friendly and holds your four factory oxygen sensors. Headers are the foundation of nearly every serious C6 build in our Tampa shop, and they pair naturally with a cat-back exhaust and a cold-air intake.

Which Kooks Header Kit Fits Your C6 Corvette?

Picking the correct kit comes down to two things: your model year and engine, and your power goal. Kooks offers the C6 headers in two primary-tube diameters. The 1-3/4 in primary is ideal for stock-to-mildly-modified naturally aspirated cars because the slightly smaller tube keeps exhaust velocity — and low-end torque — high. The 1-7/8 in primary is built for the LS7 Z06, LS9 ZR1, big-cam builds, and boosted setups that flow more air at high rpm. Every kit below is a complete header-plus-catted-X-pipe package with 3 in collectors, so you are not buying the connection pipe separately.

Kooks 09-13 Base / Grand Sport 1-3/4 in Header Kit (LS3)

Kooks 06-13 Z06 / ZR1 1-7/8 in Header Kit (LS7 / LS9)

Kooks 05-08 Base 1-7/8 in Header Kit (LS2 / LS3)

Kooks 05-08 Base 1-3/4 in Header Kit (LS2)

What Tools and Parts Do You Need Before You Start?

Long-tube headers are a moderately advanced install — budget 6 to 10 hours for a first-time DIY job and make sure you have the right equipment. A two-post lift makes the work dramatically easier, but it can be done on a jack and quality jack stands. Beyond the Kooks kit, gather these before you begin so the car is not stuck on stands waiting for parts:

• New exhaust manifold / header gaskets and header bolts or ARP header studs (some kits include hardware; confirm before ordering)
• Metric socket set with swivel joints, wobble extensions, and a 3/8 in torque wrench
• O2 sensor socket, penetrating oil, and anti-seize for the oxygen-sensor threads
• Floor jack, jack stands or a lift, and a set of safety glasses
• A tuning solution — HP Tuners or EFILive with a professional or mail-order custom C6 calibration

One rule we repeat to every customer in Tampa: only work on a stone-cold exhaust. Headers, manifolds, and cats hold heat for hours, and the O2 sensors and studs will fight you if the metal is warm. Disconnect the negative battery terminal before you touch anything.

How to Install Long-Tube Headers on a C6 Corvette: Step by Step

Installing C6 headers means removing the factory cast manifolds and OEM connection pipe, then bolting the Kooks long-tubes and catted X-pipe in their place. Always follow the printed Kooks instructions for your specific kit — the sequence below is the standard workflow we use in the shop.

Step 1: Lift, Cool, and Disconnect

With the engine fully cold, disconnect the negative battery cable, raise the car evenly, and remove the belly pans and any heat shielding that blocks access to the manifolds. On the Z06 and ZR1, take note of the dry-sump oil lines and A/C routing so you keep clearance during reassembly.

Step 2: Remove the Stock Exhaust and Cast Manifolds

Unbolt the cat-back at the connection flanges and support it out of the way. Unplug all four oxygen sensors and label them front and rear so they return to the correct bungs. Remove the OEM connection pipe and catalytic converters, then unbolt the factory cast exhaust manifolds from the cylinder heads and work them out.

Step 3: Clean the Head Flanges and Fit New Gaskets

Scrape every trace of old gasket material off the head exhaust ports and inspect the sealing surface. A clean, flat flange is what prevents future exhaust leaks. Set the new header gaskets in place — do not reuse the originals.

Step 4: Install the Kooks Long-Tube Headers

Feed each header into position, usually from underneath the car. Start every header bolt or ARP stud by hand to avoid cross-threading the aluminum LS heads, then snug them in a cross pattern and torque to the value in the Kooks instructions (LS header hardware is commonly around 15 ft-lbs — verify against your kit). A swivel socket and wobble extension are essential for the tight inboard bolts.

Step 5: Bolt Up the Catted X-Pipe Connection

Attach the Kooks GREEN catted X-pipe to the header collectors, then to the cat-back, leaving every clamp and bolt hand-tight. Align the full system so the tips sit even in the rear valance before you torque anything — tightening in the wrong order is the number-one cause of exhaust leaks and rattles.

Step 6: Reinstall O2 Sensors and Final-Torque

Apply a light coat of anti-seize to the oxygen-sensor threads and thread all four sensors back into the header and X-pipe bungs, then reconnect the harness — Kooks provides all four O2 provisions so the factory setup is retained. Final-torque the system front to back, reinstall the belly pans, and reconnect the battery.

What Torque Specs and Tuning Do C6 Headers Need?

After the install, torque the header bolts in a cross pattern to the Kooks-specified value and re-check them after a heat cycle or two, because header hardware settles as it heats and cools. Then tune the car. Long-tube headers and high-flow cats change exhaust flow and the oxygen-sensor readings enough that the factory calibration will not make the most of the hardware and can throw a catalyst-efficiency or lean code. A custom tune on HP Tuners or EFILive dials in fuel and timing for the new flow, unlocks the full 15 to 25 rwhp on a naturally aspirated build, and cleans up any post-cat O2 codes. Budget for the tune as part of the project, not an afterthought.

Common C6 Header Install Problems and How to Avoid Them

Most header headaches come down to preparation and torque, not the parts. Here is where C6 installs go right and where they go wrong.

Frequently Asked Questions