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How To Install Emissions-Legal Headers on a 2002 Corvette - Fresh Lungs

Project Twitch gets 50-state emissions-legal shorty headers

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Over the years, we've been slowly installing some of our favorite modifications onto our resident 2002 C5 Z06, also referred to as Twitch. It's not that we've heavily modified our ride; quite conversely. We've left the bulk of our upgrades to basic bolt-ons, if you will, which include the suspension, brakes, and a supercharger.

While we've addressed the exhaust from the catalytic converter back, it was only recently that we decided to make the move and install 50-state emissions-compliant shorty headers from JBA Headers.

Our main intention in this header swap was to show what it takes to get the job done. Even so, we will say that in a naturally aspirated combination, there are gains to be had and it's not uncommon to see increases of 10-plus horsepower and over 10 lb-ft of torque. For our application, Twitch is blown and we didn't anticipate a significant gain; however, we did expect to take advantage of what a quality set of aftermarket headers could offer our package.

The first of these advantages is improved airflow. Also, the ceramic coating helps reduce underhood temperatures and the headers weighs less due to its stainless steel construction. And when you consider the amount of autocrossing and open track events we attend, this is a big help for what we do. The heavy right-foot antics mixed with a power-adder would generate a bit of heat, and we were looking forward to the ceramic coating to help keep things a bit cooler. As for the reduced weight. Well, that's always an advantage in the horsepower-to-weight ratio; even with a fairly light car, we'll take the weight loss anytime we can get it.


01. For the ultimate power gain, you’ll want to go with a set of long-tube headers, which JBA offers in a 1 3/4-inch primary tube configuration. Since we’re living in an area that won’t allow long-tubes, the obvious choice for us was to go with a set of 50-state emissions-legal Cat4ward shorty headers.


02. These also feature a 1 3/4-inch primary tube and come with a 3/8-inch-thick CNC laser-cut flange. You’ll appreciate the thicker flanges, namely because it’ll prevent distortion, promoting longevity and decrease your chances of blowing the header gaskets. All tubes are mandrel bent for a smooth radius, and it even comes with oversized exhaust ports.


03. JBA offers these in three choices of coatings. The natural stainless steel is priced in at $826 or you can upgrade to your choice of silver ceramic or titanium ceramic coat for an additional $120 (priced through Summit Racing).


04. Handling the install was Kurt Hilsen from the JBA tech center. Hilsen started by disconnecting the battery then removing the three lower collector bolts. At this time, we also disconnected the O2 sensors from the exhaust manifold. We should note that while a lift isn’t necessary, it did make the header swap a lot easier.


05. Up top, we removed the spark plug wires and the plugs, and disconnected the air injection tube fittings.


06. For added room, we went ahead and removed the alternator. With the stock driver-side manifold out of the way, we cleaned up the cylinder head of any carbon deposits—there wasn’t much.


07-08. No need to stop by the local parts store for exhaust gaskets; JBA supplies a new set of multi-layer gaskets with each order.


09. Placing the header gasket over the exhaust ports, we then lowered the Cat4ward header into position and used the supplied hardware to secure it into place. We then torqued the bolts to 18 ft-lb.


10. With the header in place, we went ahead and replaced the spark plugs before moving on to the passenger side. The R&R is pretty straightforward and follows a similar procedure.


11. To complete our install, we swapped out the original spark plug wires and installed a new set of JBA PowerCables (PN 0807-9). These feature a spiral-wound stainless steel alloy with carbon impregnated fiberglass center core that features a low 500-ohm-per-foot resistance. If there was one thing we immediately noticed, it was the smoother idle quality.


12. And there you have it. These fresh headers even come with a sticker to show its 50-state emissions compliancy, and needs to be placed under the hood, should any questions ever arise.

Weighing In…

Just out of curiosity, we wanted to see how much weight we saved from swapping over the cast-iron Z06 exhaust manifolds with the stainless steel JBA Cat4ward shorty headers. The final numbers revealed an impressive 16.65-pound weight reduction, which is pretty significant at more than half the weight of factory counterparts.






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