The fourth-generation Pontiac Firebird Trans Am already had plenty going for it from the factory. By 1999, the LS1 V8 had established the F-body as a serious performer, with the WS6 package adding an even more aggressive appearance to Pontiac’s muscle car.
More than 25 years later, the platform has become an appealing starting point for builders chasing substantially bigger performance. LS-based engines respond particularly well to modification, while the fourth-gen’s relatively low weight gives tuners plenty to work with.
Cornell’s black 1999 Trans Am takes that potential much further without turning the car into an unrecognizable track machine. At first glance, the drag-oriented wheels and carbon-fiber pieces offer the biggest clues that something serious is hiding underneath.
Pop the hood and any remaining doubt quickly disappears. Featured by the Autotopia LA YouTube channel, this WS6 packs a heavily modified 6.0-liter LS-based V8 running on E85 and producing over 600 horsepower at the crank.
A Naturally Aspirated LS That Loves Revs
Rather than relying on forced induction, Cornell wanted the Trans Am to make its power the way God intended — naturally aspirated. The engine was built by CNC Motorsports in Compton and uses a 6.0-liter block bored to 6.2-liter dimensions before being destroked to 339 cubic inches.
The combination includes LS3 cylinder heads and upgraded internal components, with the engine capable of revving to around 8,000 rpm. Cornell says it makes over 600 horsepower at the flywheel, while dyno results put output somewhere in the mid-500-horsepower range at the wheels.
E85 provides the fuel, and the engine breathes through 1-7/8-inch Kooks headers connected to a three-inch exhaust system. During Autotopia LA’s drive, the Trans Am remained relatively manageable at lower engine speeds before becoming considerably more aggressive around 5,000 rpm.
There’s A 300-Shot Waiting In Reserve
Apparently, 600-plus horsepower wasn’t enough preparation for the future. The Pontiac has also been fully plumbed for nitrous, with the bottle installed in the rear and a programmable controller discreetly integrated into the otherwise mostly stock-looking cabin.
Cornell says the system can support up to a 400-shot, although he plans to limit it to a maximum of 300 horsepower. It has not yet been tuned for nitrous, so that potential output is just theoretical for now.
The controller allows nitrous delivery to be progressively adjusted according to engine speed rather than unleashing everything immediately. Cornell also intends to install a roll cage, an understandable addition if the car ultimately reaches the sub-10-second quarter-mile territory he expects.
Built To Put The Power Down
A built 4L60E automatic transmission handles the engine’s output, while the suspension uses Bilstein dampers and Eibach lowering springs. Cadillac CTS-V brakes have been fitted up front, with the factory braking setup retained at the rear.
The drag setup consists of 17-inch skinny front wheels and 15×10-inch Race Stars at the rear wrapped in 295-section tires, the widest Cornell says he could fit. He has already bought a second set of front wheels and tires for everyday street driving, allowing him to swap out the skinnies when the Trans Am isn’t heading to the drag strip.
Carbon Motorsports supplied a carbon-fiber hood, T-bar, and rear wing, trimming weight while giving the black Pontiac a more purposeful appearance. Bronze-colored wheels provide one of the few contrasts against the otherwise dark exterior.
Still Surprisingly Civilized
Perhaps the most interesting aspect is how much of the Trans Am’s original character remains inside. Cornell deliberately retained the stock interior appearance, adding only the instrumentation and controls necessary to monitor the modified drivetrain.
Its “modest” looks make the performance hiding underneath even more entertaining. The Trans Am can cruise without constant drama, yet once the tachometer approaches 5,000 rpm, its high-revving LS completely changes character.
The nitrous system could eventually make it considerably quicker. Even without touching the button, though, a naturally aspirated, E85-fed fourth-gen producing over 600 horsepower sounds like plenty of entertainment.