Now that the LS1 engine has proven itself to be the best-performing pushrod engine ever built, it seems ludicrous that its power-producing capability was ever doubted. And to add insult to the injury suffered by the doubters, the LS1 has also demonstrated that it maintains the tradition of its predecessor in responding enthusiastically to performance-enhancing modifications.
One of the easiest-and most rewarding-LS1 modifications is the installation of headers combined with an exhaust-system upgrade. Specifically, a set of TPI Specialties long-tube headers combined with a Random Technology stainless steel 3-inch converter/X-pipe assembly and exhaust system, bumped the peak rear-wheel horsepower of a stock '01 roadster from 297 to 337-an increase of 40 hp.
According to Corvette specialist Jody Gregg of Speed Hound Performance, "Installing headers and an exhaust system on a C5 is relatively easy-especially with this combination of equipment. Everything bolts together so there's no welding or fabrication involved. And as the dyno numbers show, you get a big increase in power across a pretty wide rpm range." When you compare the numbers, you see that from 3,700 to 4,400 rpm the increase is over 20 hp; from 4,500 to 5,200 the increase is over 30 hp; and from 5,300 to 6,000 the increase is over 40 hp. Keep in mind that this is a stock engine. The increases would be even greater if internal modifications had been made or a supercharger had been installed. Although you'll find any number of advertisements claiming that a few minor tweaks will deliver "massive" power gains, in the real world a 10 percent boost in power isn't easily achieved. As is the case with the engine itself, the key lies in the overall combination of components. Individually, headers, high-flow catalytic converters, and a low-restriction converter-back exhaust system will all deliver measurable gains. But when the right parts are combined, the whole equals more than the sum of the parts.
However, since not all C5 owners may want to install long-tube headers, Random Technology offers converter/X-pipe assemblies to fit stock exhaust manifolds and shorty headers. The company has also developed a 3-inch converter/X-pipe assembly, and a matching 3-inch converter-back exhaust system. This system is designed for maximum output applications, but has proven to be worth a few horsepower on a stock engine.
As the accompanying photos illustrate, installation of all components is fairly routine and can be accomplished by anyone with a reasonable amount of wrench-turning experience. If you decide to do the installation yourself and haven't worked on a C5 before, keep in mind that the LS1 is a "metric engine," requiring-you guessed it-metric tools. Also, check your local emissions legislation to ensure compliance with local requirements.