How to Install Exhaust Headers on a Performance Car

Adding a set of aftermarket headers is a surefire way to make a naturally aspirated or even turbocharged engine run faster.  Installing a header is an important part of a performance build, whether you want to increase horsepower, lower exhaust restriction, or just make the flow more efficient. Understanding what is an exhaust header and how to install it correctly helps you avoid leaks, clearances issues, and performance losses.

What Are Exhaust Headers?

Before getting into how to install exhaust headers, it's helpful to understand how they function and how they differ from stock manifolds. Most factory manifolds are big pieces made of cast iron that were made to save money and make less noise.  Even though they work, the uneven pipe lengths and tight bends tend to stop airflow.

Headers, by contrast, are performance-minded replacements made with smoother, equal-length tubing that routes exhaust gases from each cylinder into a collector. This design increases power and airflow by encouraging effective gas evacuation.

How Do Exhaust Headers Work?

To understand how do exhaust headers work, think of how combustion gases exit your engine. After the air-fuel mixture burns in the cylinder, the exhaust gases need to leave the chamber as fast as possible. Headers are built to streamline this flow.

By making each runner the same length, headers ensure that exhaust pulses arrive evenly at the collector. This spacing reduces the chances of pressure buildup and creates a scavenging effect, where the gas flow from one cylinder helps pull gases from the next. Particularly at faster RPMs, this technique enables the engine to breathe more effectively and may produce noticeable horsepower increases.

What You’ll Need

Before removing anything, gather essential tools and materials to make the process smoother. These often include a jack and jack stands or a lift, socket sets, wrenches, a torque wrench, header gaskets, penetrating oil, high-temperature anti-seize compound, and safety gear like gloves and glasses. A gasket scraper is also useful for cleaning the cylinder head surface once the old manifold is off.

Preparation

Start by letting the engine cool completely. Working around hot exhaust parts is dangerous and will make the job far more difficult. Disconnect the battery to avoid any electrical mishaps while handling tools near wiring or sensors.

Lift the vehicle to allow access underneath the engine bay. Spraying penetrating oil on bolts now gives it time to work while you prepare.

Removing the Factory Manifold

Begin by taking off any heat shields that may be blocking access to the exhaust manifold. Unplug any oxygen sensors from the existing manifold and move them out of the way. Then loosen and remove the manifold bolts connecting it to the engine. You may need to reach from underneath for better access to some bolts.

When you take off the manifold, use a gasket scraper to clean the cylinder head of any debris that is still there.  For a good seal and to stop exhaust leaks, the surface must be clean.

Installing the New Headers

Place a fresh header gasket onto the cylinder head, lining it up with the ports. Then position the header in place and insert the bolts by hand to hold it. Once everything is lined up correctly, tighten the bolts following the recommended torque sequence, starting from the center and working outward to distribute pressure evenly.

Next, connect the header’s outlet flange or collector to the exhaust system. Depending on your vehicle, this may require alignment with the mid-pipe or downpipe. Make sure to use proper gaskets or clamps to avoid leaks at the connection point.

If the new headers have O2 sensor ports, thread in the sensors and reconnect their wiring. Secure all wiring away from the hot pipes using high-temperature-resistant ties or brackets.

Use anti-seize compound on bolts during reassembly. This simple step can make any future removal much easier, especially after extended heat cycles.

Final Checks and Startup

After securing everything, lower the vehicle and reconnect the battery. Start the engine and let it idle. Listen closely for ticking noises that might suggest a leak at the head flange or collector. You can also feel around the joints (at a safe distance) to check for escaping exhaust gases.

If everything sounds and looks good, take the vehicle for a short, low-load test drive. After returning, inspect all bolts again to ensure none have loosened due to heat cycling. Rechecking torque is a good habit when dealing with exhaust systems.

What to Expect After Installation

Once installed properly, headers can offer immediate benefits in performance and drivability. You may notice faster throttle response and increased mid-to-high RPM power. Many vehicles also see a deeper, more aggressive exhaust tone.

Although the benefits will differ based on the rest of your configuration, headers offer a good basis for other performance enhancements, including tuning and intake changes.  Whether your goal is a track car or a lively daily driver, car enthusiasts still love this improvement.