When performed correctly on any car that needs them, exhaust upgrades accomplish three things: Your car will be quicker, have an authoritative tone, and run more efficiently. With those benefits in mind, we decided to bolt a set of American Racing Headers' 1.875-inch headers and free-flowing cats onto an '05 GTO. The Goat in question was previously fitted with an after-cat system from Corsa. Since the new components are the next logical step toward power production, we proceeded with them.
Manufactured in 304 stainless steel, American Racing's headers are strong, look great, and shouldn't corrode if properly cared for. They also feature a merge collector with a scavenger spike. "Merge collectors are a staple of our headers here at American Racing Headers," says Nick Filippides, the company's project manager. "We found the merge allows us to maintain strong low-end torque, without having to sacrifice top-end horsepower. We use the scavenger spikes to direct the exhaust through the 3-inch collector."
Though this technology isn't uncommon on many of today's high-end header systems, it usually comes at an additional cost. American Racing's headers, however, are sold with this NASCAR-derived feature as standard equipment.
According to the company, the gains we saw could have been higher if we had opted for the smaller 1.75-inch primary headers, as they would've been more appropriate for such a tame GTO. We went for the larger tubes because planned future mods will require them to produce the most power.
The first step was to establish a baseline. Our '05 GTO benefits from a Corsa Sport after-cat but is otherwise stock down to the paper air filter. Attached to the Dynojet rollers, the GTO put down 325 rwhp and 325 lb-ft of torque. These figures were supported by another backup run.
The components were installed at AntiVenom LSX Performance and Repair in Seffner, Florida. This company specializes in late-model GM performance buildups on Corvettes, F-bodies, and GTOs. Let's follow along as owner Greg Lovell and William Edgar remove the restrictive stock exhaust and install the shiny, free-flowing parts from American Racing Headers.
Conclusion
The installation of the header system was good for a solid 19 rwhp and 24 lb-ft of torque. Afterwards, AntiVenom's Greg Lovell altered the tune a bit and picked up an additional 6 rwhp. After all was said and done, our GTO gained 25 rwhp and 21 lb-ft of torque.
Throughout the powerband, there was a consistent gain. Down low through the midrange, torque picked up substantially. This can be felt on the street as we now have a tough time keeping traction. When it does hook, the power and sound are brilliant.
For anyone who has ever installed a long-tube header system on a late-model car, the installation was straightforward. The results are worth the effort.
