How to Install Corvette Headers and Side Exhaust

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How to Install Corvette Headers and Side Exhaust

Corvette Header Clearance
You can see here how the headers bring the exhaust out to the side of the car. Headers and side exhausts look great and generally offer better performance than a stock exhaust system. Photo by Jeff Zurschmeide

One of the all-time great things about Corvettes is the way the GM V8 engines lend themselves to sexy side-exhaust systems. For the uninitiated, a side exhaust is when the exhaust pipes run along the bottom of the bodywork between the front and rear wheels. This design was developed early in the history of the automobile and allows for a more direct and unrestricted exhaust system while also providing increased underbody clearance and less heat transferred into the cabin.

With any engine, de-restricting the exhaust path is an easy and simple way to increase horsepower and torque. Simply put, if your engine doesn't have to use power to push the exhaust gasses out the back of the car through a narrow and winding passage, it can use that power to drive the car instead. So, with certain caveats, a free-flowing exhaust is better than a restricted exhaust. However, there are those caveats. The first being that if the exhaust is too free-flowing, you won't get as much velocity in your exhaust gasses, and that velocity helps with high-rev horsepower. The other caveat is that headers and side exhausts tend to be much louder than stock, and this can get you in trouble with the police - check your local laws! Also, if your Corvette was made after 1975, you need to think about your catalytic converter.

But if you want to put headers and side exhaust (side pipes) on your classic 'Vette, you can follow the steps in this article. Be aware that it involves cutting your bodywork on C3 (68-82) Corvettes!

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Choose a Header and Exhaust System for Your Corvette

Corvette Headers - Example Header
Here's a look at one of the Hooker headers we used on the 1977 project Corvette. It comes as a set with the side exhausts in basic black or in Chrome. Photo by Jeff Zurschmeide

Unless your Corvette came with factory stock side exhausts, you'll need to locate and purchase an exhaust system. These vary widely in price and features, but are generally available from online Corvette parts suppliers such as Corvette Central or Eckler's Corvette.

Be aware that big blocks and small blocks will take different systems, and that you may want to choose a different diameter of primary header tubes for different horsepower outcomes. Bigger tubes won't generate as much high-end horsepower. Ideally for a basically stock 350 cubic inch engine, you'd get primary tubes of about 1.5 inches. The Hooker system we bought uses primaries of 1.875 inches.

With a full aftermarket system, you can (and should) also buy muffler inserts for your side exhausts. The inserts designed for the Hooker system are available in 2-inch, 2.25-inch, and 2.5-inch sizes. We bought the 2.5-inch inserts and they're louder than we'd like. We'll be investing another $200 or so and getting the quieter 2-inch variety.

Note that some versions will use the stock exhaust manifolds and just bring a single pipe out to the side of the car. These tend to be smaller and will require decorative coverings - but they're also street-legal quiet. So you can choose among many options.

Finally, be aware that side exhausts get very hot, and they are perfectly positioned to burn your leg when you exit your Corvette. So consider some heat shields, or at least consider having your side pipes ceramic-coated to minimize external heat.

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Install the Headers in Your Corvette

Corvette Header Installed
One side of the Corvette headers is installed loosely to test the fit. You want to check the frame rails and the sides of the bodywork. Photo by Jeff Zurschmeide

The first step that involves a wrench is to install the headers in your Corvette. This is easiest to accomplish in conjunction with an engine transplant, as we did, but you can do it at any time.

Remove your old exhaust system entirely and test-fit the headers. You may need to carefully adjust the headers with a hammer and drift to clear the frame rails. You don't want them rattling!

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Mark Your Corvette Bodywork for a Clearance Notch

Corvette Headers - Body Marked For Notching
Here's the skirt of the bodywork, with marks to show us where to notch a little bit out of the fiberglass to accommodate the new headers without touching. Photo by Jeff Zurschmeide

With the headers loosely installed, you'll notice that they touch the bottom skirt of the bodywork along the side of the car. There's a trim piece on each side of the car that will need to be removed to mount the pipes, and you'll need to cut that piece as well to fit the particular set of headers and pipes that you've purchased.

But what you want to do now is mark the forward and rearward extents of the bundle of primary pipes, so you can trim up about 1/2 to 3/4 of an inch of the skirt. A Dremel-type rotary cutter works best for this job. Mark your bodywork as shown in the photo and make your cut.

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Tighten Down the Corvette Headers

Corvette Headers - Skirting the Fiberglass
Here you can see where the notch in the skirt of the car's bodywork accommodates the headers. Photo by Jeff Zurschmeide

When you've notched the body skirt on both sides of the car, you can go ahead and tighten down the headers at the engine. As you tighten them down, the headers will move some, so keep a close eye on your clearances.

At this time, you'll want to put your inserts into the end of the header and fit the side exhaust pipes. These have their own mounting tabs, and you might need to drill the frame rails to install them. They also come with rubber mounting pads, and you want to use these to isolate the pipes from the chassis to prevent excessive vibration.

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Enjoy Your New Corvette Headers and Side Exhausts

Corvette Header and Side Exhaust
Here's the header and side exhaust all installed and working. It's quite loud!. Photo by Jeff Zurschmeide

When you first fire up your Corvette after the installation, be aware that the system may smoke quite a bit as oils from the manufacturing process and from your hands burn off. You may also find (depending on your year and model) that you need a bracket or two to remount your alternator or A/C pump. These brackets come with the Hooker ​kit, and are also available separately. I bought the alternator bracket separately, and one came with the kit, and I didn't even need them for my Corvette! So I have two spares if you need them.

Be forewarned - this new exhaust is going to be extremely loud. So if you finished the install at midnight, don't test-fire the car if you don't want to wake up your whole neighborhood. But when you do fire it up, it's guaranteed that your Corvette will sound like a snarling beast. And that's always a good thing.