Inside the Magic of Kooks Custom Headers

If you’re talking cars and you drop the words hand-made or custom, the first thing that comes to mind is quality. Something that is hand-made will always have a personal and even a little mystical feeling to it. The guys at Kooks Custom Headers are people that believe in just that. 

The history of Kooks Custom Headers can be traced back to 1962, when George Kook Sr. used his gas torch to build his first set of headers for the family race car. Being heavily involved in racing, his talents did not go unnoticed by all the local competition he would beat on the strip. Over the past 40 years Kooks has been on the leading edge of header performance, supplying parts for some of the biggest names in street-legal racing. The company has grown from one man and his gas torch to a full production manufacturing facility. 

Unlike most header companies, Kooks prides themselves on being a true “custom” shop. Without the aid of a lot of automation, their workers still to this day make some of the best headers for any application the same as Mr. Kook did by hand. It is this what gives their headers that custom feel without the custom cost. They offer a street- and track-tested header for almost every application of late model cars and trucks.

Research & Development
When designing headers for a specific vehicle, Kooks lays out the prototype on the actual car to make 100% sure that the kit will fit seamlessly. Using their extensive involvement in racing and their street customers’ feedback, they constantly evolve their designs. When it comes to testing their headers, Kooks always uses a third party for their dyno testing. This insures unbiased performance numbers that will best represent the real world results you would find if you dyno tested the system yourself. This honest approach helps in a world where companies throw out big numbers to persuade you to buy their product. The performance numbers should be able to reassure someone that they are making the right purchase, not the other way around.

How the Headers are Made
Kooks isn’t interested in trying to reinvent the wheel when it’s not necessary. For headers destined for the street, they reference factory designs, which have countless hours and dollars put into them. Kooks uses their years of experience and knowledge to extract as much performance as possible while keeping price and ease of installation in mind. To control costs while maintaining quality, Kooks buys their raw tubing in bulk, cutting and bending in-house as needed. Kooks uses 304 stainless steel for their top-of-the-line headers. While this alloy is a tad bit pricier, they’ve found it will not flake or crack like many lower grades of steel.

The next step in the process is to take the straight tubing and bend it to the degree needed. All of Kooks’ headers are mandrel bent. This process keeps the diameter of the tubing the same thoughout the bend to maximize airflow by reducing restriction. These newly-formed primaries are then sent over to a storage area where the await an order. One an order for a production run comes in, all the straight tubes, bends, O2 bungs, and anything else needed are pulled from inventor and taken over to the assembling area.

A worker places the parts on a jig and TIG welds all of the parts together. That’s right, hand welded. You won’t find any robots here. The newly-formed headers are then hand-ground and ported. It is this step that sets Kooks apart from many of the top header makers. Welding, grinding, and porting everything by hand adds a quality control step. If something isn’t working right or doesn’t seem to fit like it should, the worker removes it from production.

Top 5 Tips on Headers from Kooks
I was lucky enough to speak to George Rumore from Kooks, and I got him to spill the beans on some things to look out for when picking tubes for your car or truck. Now I’ve heard stories about building headers from every guy and his mother, but Rumore summed it up best when he said, “When it comes to building headers there are theories, and then there is science. We [here at Kooks] use science.” Let’s put some of these theories to the test:

Theory Number One: “It doesn’t matter what my headers are made from.”
As is turns out, the material that your headers are made from can actually affect your engine’s performance. Mild steel may sound good with its lower price tag and easy availability, but untreated mild-steel absorbs heat and likes to hold on to it for as long as it can. “If you were to go out and make a run with mild steel headers, they are going to be hot for a good 30-45 minutes,” said Rumore, “versus a 304 stainless steel header in the same situation cooling down in 10-15 minutes.” Keeping the temperature down in the engine compartment can help you with everything from lowering intake temperature to being able to wrench on the car faster without worrying about burning yourself.

Theory Number Two: “The less bends, the better performance.”
In plain terms, an engine is just a few air pumps smashed together. “You want all of the primaries to be close to the same length; that way the pressure is more even throughout the system,” explained Rumore. Extra backpressure is caused when two cylinders’ exhaust pulses reach the collector at the same time. As we all know, cylinders don’t usually fire at the same time on the same side of the engine, so as long as the primaries are close to the same length the pulses with reach the collector at different times. By changing the bends of the tubes you can make the primaries close to the same length. Now I’m not saying that the more bends, the better either; you still want to keep the amount of bends to a miniumum. but sometimes you might need to add an extra kink.

Note the lengths of the primaries. Sometimes it takes a little creativity to find a way to keep them all the same.


Theory Number Three: “The bigger the tubing, the more airflow and power.”
Sorry guys; in this case bigger isn’t always better. While bigger tubing will increase potential airflow, too big will kill your back pressure and negate any gains from the ‘plus sizing’ of the tubes you though you were going to get. “At Kooks we use our R&D to find the optimal sizing for each engine we sell headers for,” Rumore told me. If just adding bigger tubing was the answer then we would all just run our cars with no exhaust for maximum airflow out of the engine.

Theory Number Four: “Just make it fit!”
When picking a header for your vehicle you must keep in mind that you need something that works in conjunction with your engine and your vehicle. I’m not just talking about engine size and power but also how the headers will fit in the car. Kooks can help you build a header that works well with your engine using their database of racers and customers that have a wide variety of engines and applications. As for the rest of your vehicle, the rest of the exhaust should be considered. A quick call to Kooks will set you straight and make sure you not only get the right parts you need but a understanding of why you need it.

An extensive inventory of components means that Kooks can come up with the right solution for practically every application.


Theory Number Five: “I’ll just weld a turbo to the headers I got now.”
Yup, most of you I’m sure guessed it. Headers for a turbo application are extremely different than those for a N/A setup. The main difference, besides the fact that a turbo is part of one and not the other, is the design to control the airflow. In a turbo exhaust you want a little bit more pressure to help the turbo spool up faster. Too much or too little and it will spool up slower and rob you of the power you will be looking for.

So What Does All This Mean?
To put it bluntly, there is a lot more to making headers than just piecing together some pipes and connecting them to an engine. There are countless hours of R&D that go into the best headers on the market, and for good reason. When you are going to pick out a set for your vehicle, if you keep these things in mind you will get a product that you are much happier with. The guys at Kooks can make it so you have the best experience possible in buying and using headers, and they are only a click or a phone call away. Or, if you’re lucky enough to make your way to an NMCA or NMRA race this year, make time for a quick stop to the Kooks tent or watch the cars win with their stuff on the track.

Be sure to check out all of the photos from our shop tour in the photo gallery.

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About the author

Jeff Huneycutt

Jeff Huneycutt has been in the automotive industry long enough to collect more project cars than he can afford to keep running. When not chasing electrical gremlins in his '78 Camaro, he can usually be found planning unrealistic engine builds.
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