The year 1988 would mark the Buick Regal's change from its old rear-drive G-platform to a new front-drive W-platform, but also signaled the end of the Grand National - arguably, one of the sportiest Buicks built since the 1970s. To celebrate - and go out with a bang - Buick decided to build the ultimate Grand National: the 1987 GNX.
GM engineers began work on the project in late 1986, partnering with colleagues at American Sunroof Company and McLaren Engines to develop the program. Given the budget and time constraints, no party had time to re-work the innards of the Grand National's 3.8-liter turbocharged V-6 - but they could work on external components.
The motor was treated to a modified Garrett T-3 turbocharger with a ceramic impeller, revised intake and exhaust systems, a larger intercooler, and a tweaked engine computer. These changes yielded 276 hp and 360 lb-ft of torque - a significant boost from a base Grand National, which in 1987, delivered only 245 hp.
They also yielded some impressive performance figures. Two GNX prototypes hit a drag strip in 1986, laying down a 0-60 time of 5.38 seconds, and made a quarter-mile sprint in 13.47 seconds at 104 mph - outperforming a naturally-aspirated Porsche 911 and even Chevrolet's own Corvette.
Some mild chassis changes (like new rear torque bars and a Panhard rod linkage) helped channel that power to the ground, but the GNX remained a sleeper. With a monochromatic black exterior, all production cars looked nearly identical to a normal Grand National, save for small emblems, fender portholes, cross-lace alloy wheels and analog gauges for the driver.
Such performance didn't come cheaply; the GNX option package ran for nearly $10,000, bringing the total price for a car to a whopping $29,900 (nearly $57,000 in today's economy). That didn't deter buyers; Buick had to raise production figures from an initial cap of 200 cars to 500 to meet demand. Ultimately, 547 examples were built, making the 1987 GNX one of the most collectible - if not powerful - Buicks to date.