Upgraded Chevy C6 Corvette Headers Guide

The C6 Corvette is widely considered to be one of the best American sports cars of all time. After the mid-production switch to the LS3 engine in 2008, the C6 produced 430 horsepower and 424 lb-ft of torque from the factory. Those are unarguably impressive numbers. However, the real kicker is the C6’s willingness to take on even more ponies from aftermarket upgrades. That’s where upgraded C6 Corvette headers enter the picture. Upgrading to performance headers is one of the least expensive upgrades that you can do to see sizable power and torque gains.

The world of C6 headers is a massive one that you can sink a lot of time into. For the purpose of this article, we’ll stick to the basics. We’ll primarily cover what C6 Corvette headers are, the different types of headers available, and provide some suggestions towards the end. 

C6 Corvette Long-tube vs Short-tube Headers

Wherever there’s a discussion about headers, the subject of short-tube (or shorty) vs long-tube headers inevitably arises. The difference between the two really is contained in their names. The primary tubes on C6 shorty headers merge into a collector in a much shorter distance than with long-tube headers. The opposite is the case for long-tube headers.

The difference in primary tube length between short and long-tube Corvette headers makes a significant difference in terms of how the LS3 engine performs. As the LS3 in your C6 Corvette runs, exhaust gasses are released into the headers in pulses. The length of the primary tubes directly affects where in the power and torque curves extra power is generated. As a general rule, shorty headers scavenge exhaust gasses quicker by shortening exhaust gas pulses, which increases horsepower and torque in the lower rev range. Inversely, long-tube Corvette headers lengthen exhaust gas pulses, which move horsepower and torque gains higher up the rev range. 

While it is certainly possible to see noticeable gains from short-tube headers, it is pretty much unanimously concluded that long-tube headers are the way to go on an LS3 C6 Corvette. If you are strictly concerned with performance, especially high in the rev range, long-tube headers will yield the best results. While short-tube headers will unquestionably flow better than the factory C6 exhaust manifold, lower cost, and better fitment are often the more persuasive reasons to go for shorties than the performance gains.

Catless vs High-Flow Cats

The C6 Corvette in factory form came with either 2 or 4 catalytic converters depending on the model year and your location. 2008-2011 C6 Corvettes came with only 2 catalytic converters, while 2012 and newer C6 models came with 4 cats in the mid-pipe. Obviously, the more cats are introduced into the exhaust system, the more restrictive the system is as a whole. In factory C6 Corvettes, the catalytic converters are placed between the exhaust manifold and X-pipe. While some short tube headers allow you to retain the factory cats, most long tube headers will require you to work out a new cat solution. 

When it comes to Corvette performance headers, there are typically two options as far as catalytic converters are concerned. You can either run C6 headers that retain catalytic converters or run some with no cats at all. Before we go any further, it is important to remember that going catless is illegal in most US states. That fact makes catless headers and X-pipes a strictly off-road upgrade. With catless long-tube headers, you won’t be able to pass an emissions test. With that being said, catless Corvette headers and X-pipes will yield the biggest performance gains.

The other option is finding a set of long-tube headers with high-flow catalytic converters installed. Most aftermarket catted header options come packaged with an X-pipe as well. The typical cat relocation solution is including the cats within the X-pipe. While you might not see as impressive of gains as you would see from a fully catless header option, high-flow catted Corvette headers are the better option overall. They’ll keep your Vette emissions legal while still providing sizable horsepower and torque gains overall. 

Benefits of Upgraded Headers

The potential benefits of upgrading your C6 Corvette headers are extensive in terms of both performance and sound. Obviously, the horsepower and torque yield from an LS3 header upgrade can vary a significant amount. As we covered above, there is a discrepancy in power gains, and where in the rev range the power is produced, based on the type of header that you choose and whether or not you run a high-flow or catless option. Here are some of the most straightforward gains that you can expect to see from upgraded C6 Corvette headers:

Long-Tube Header Gains:

• (Catted) 10-20 hp gain w/ similar torque gain with tune
• (Catless) 20-30 hp gain w/ similar torque gain with tune
• Notable increase in power in the mid-high rev range between 4,500-6,000 rpm
• Reduced backpressure
• Lower exhaust gas temperatures
• Better exhaust scavenging characteristics
• Improved exhaust sound

Short-Tube Header Gains:

• (Catted) 5-15 hp gain w/ similar torque gain
• Notable increase in power in the low-mid rev range between 1,500-3,500 rpm
• Reduced backpressure
• Lower exhaust gas temperatures
• Better exhaust scavenging characteristics
• Improved exhaust sound

Corvette Header HP Gains

Looking at the figures listed above, it is pretty clear that if performance is the goal, long-tube C6 headers are the way to go. The increased power gains from long-tube headers are due to primary tube length and diameter and their effect on exhaust scavenging. Most long-tube headers are meticulously designed to interact with exhaust gas pulses in a way where the maximum amount of negative pressure is created in the headers to pull exhaust gas out of the cylinder as fast as possible. This “scavenging” effect is the key to increased performance and is something that long-tube headers do very well.

Backpressure is another crucial factor that can be reduced with upgraded Corvette headers. Backpressure is caused by resistance within the exhaust system, whether it be by catalytic converters or non-optimized piping diameters. Both long-tube and short-tube C6 headers can decrease backpressure by decreasing the amount of resistance that exhaust gasses encounter. That results in increased horsepower. 

In general, long-tube Corvette headers tend to do a better job of improving exhaust scavenging and reducing backpressure and therefore generate better performance gains. That is especially true with catless long-tube headers. With that being said, there are arguments for short-tube headers as well. They are typically less expensive, easier to install, look good in the engine bay, and improve exhaust tone. However, they aren’t the way to go if peak performance is the mission.

Best C6 Corvette Headers

With all of the basics out of the way, let’s talk about some of the best C6 Corvette header options on the market currently. Since headers are such a popular modification for the C6, there are quite a few solid options out there. That goes for both catless and high-flow catted header options. While long-tube header options are by far the most popular option, we’ll also throw in a short-tube option as well. 

• C6 Corvette Kooks Headers 1 3/4” With High Flow Cats
• Texas Speed & Performance 1-⅞” Long-Tube Catless Headers
• Hooker Blackheart 2005-2013 Short-Tube Headers
• LG 05-13 Corvette Super Pro LS3 Long-Tube Headers

Our Number 1 Pick – C6 Corvette Kooks Headers 1 3/4” With High Flow Cats

Price: $2,445.30

Compatibility: 2005-2008 LS2 C6, 2009-2013 LS3 C6

Style: Long-Tube

Purchase Here: Corvettepartsandaccessories.com

In most C6 Corvette header discussions, you can’t scroll for more than about 10 seconds without the name “Kooks” making an appearance. They are a manufacturer known for their superior build quality and attention to detail. Kooks has concentrated on performance headers and exhaust components for American racing applications for the better part of 50 years. 

The Kooks C6 Corvette Long-Tube header set comes with the complete package to get your C6 exhaust up to snuff. The kit comes complete with a set of T304 stainless steel long tube headers with sizable 1 ¾” primaries, a high-performance X-pipe with high-flow cats, new gaskets, O2 extensions, and exhaust clamps. In short, it comes with everything that you need to get up and running. 

In addition to 1 ¾” primary tubes, Kooks also has 1 ⅞” and 2” primary options available as well for those looking to move to forced induction in the future. The 1 ¾” suggestion comes from the standpoint of good naturally aspirated drivability. Without forced induction, large primary tubes will have little to no performance benefit. 

C6 Corvette Headers Upgrade Summary

Upgraded headers are one of the most significant and talked-about modifications that you can do to your C6 LS3 Corvette. The benefits over the stock C6 exhaust manifold are significant in increasing exhaust flow and providing better exhaust scavenging which equates to better performance overall. Since upgraded C6 Corvette headers are such a popular modification, there are a ton of aftermarket options available. The key is finding the right set of headers for your needs.

One of the most important considerations is the catalytic converter arrangement. While catless C6 headers will unquestionably provide the best performance, they present other issues. Catless headers are made for track use only and will cause your C6 to fail an emissions test. If you are looking for the best gains while remaining road-legal, a set of long-tube C6 headers with high-flow cats is your best bet. 

Long-tube Corvette headers are the go-to choice in the LS community. That boil down to their superior scavenging and backpressure-reducing qualities. Long-tube headers will provide the best mid-high rpm performance, but they are often more expensive and harder to install than short-tube headers. While shorty LS3 headers aren’t the best choice for power gains, many people like them for their easy fitment, compatibility with factory catalytic converters, enhanced exhaust tone, and lower price. 

If you enjoyed this article and are looking for more Vette content, check out our Best Chevy LS3 Engine Upgrade Guide and Corvette C6 Seat Upgrade Guide. As always, safe driving!