This article contains affiliate links. If you click a link and make a purchase, we may earn a small commission at no extra cost to you.

1984–1987 Buick Grand National / GNX

The turbocharged V6 Buick was the ultimate sleeper. The 1987 GNX, built with ASC/McLaren, embarrassed Corvettes and Ferraris, running 0-60 in 4.7 seconds. It proved muscle didn't need eight cylinders.

1984–1987 Buick Grand National / GNX — Full Specifications

  • Engine: 231ci (3.8L) Turbo V6
  • Power: 245–300 bhp
  • Torque: 355–400 lb-ft
  • Transmission: 200-4R 4-speed automatic (only transmission offered)
  • Drivetrain: Front engine, rear-wheel drive
  • Body style: 2-door coupe
  • Wheelbase: 108.1 inches
  • Curb weight: 3,400–3,600 lbs (GNX: 3,545 lbs)
  • 0–60 mph: 4.7 sec (GNX); 5.5 sec (Grand National)
  • Quarter mile: 13.4 sec (Grand National); 12.7 sec (GNX, as tested by Motor Trend)
  • Original MSRP: $16,697 (1987 Grand National); $29,290 (1987 GNX)
  • Current value: $35,000–$65,000 (Grand National); $80,000–$150,000 (T-type); $130,000–$250,000+ (GNX)

Production Notes

The GNX produced a factory-rated 276 hp, but dyno testing showed actual output closer to 300 hp. Only 547 GNX models were built, all in 1987. The Grand National name comes from Buick's NASCAR Grand National racing heritage.

Notable Factory Options

  • GNX package (547 built)
  • T-top roof
  • WE2 turbo package
  • G80 Positraction
  • Performance exhaust
  • Leather interior

Buying Guide

The Grand National/GNX is one of the most rapidly appreciating muscle cars in the market. The 1987 is the best year—the final year with the most refined engine management and highest power. 1984–85 Grand Nationals (T-type trim with turbo) are the affordable entry and have excellent appreciation potential. 1986 Grand Nationals are nearly identical to '87s mechanically and about 20% cheaper. The GNX is a finite collectible (547 built) with a fanatical following—buy the best one you can afford. Non-turbo Regals and naturally aspirated Grand Nationals exist—they are not collectible. Verify the turbo V6 by checking the VIN (7th character: '7' = turbo V6). A compression test and boost leak test should be part of any pre-purchase inspection. The 200-4R transmission is the Achilles heel—budget for a rebuild or upgrade.

Pros

  • The ultimate 1980s muscle car—faster than anything in its era
  • GNX is a proven investment with strong appreciation
  • Turbocharged platform responds incredibly well to modifications
  • All-black stealth styling is timeless
  • Strong dedicated community and turbo Buick specialists

Cons

  • 200-4R automatic transmission is fragile under boost
  • No manual transmission option was ever available
  • Turbo V6 parts are model-specific and can be pricey
  • G-body platform shows its age in handling and refinement
  • GNX prices have risen to the point of limiting buyer pool

Restoration Tips

Turbo V6 parts are specific to this application. Turbocharger upgrades are well-documented. Body panels are shared with other G-body cars. Watch for boost leaks and intercooler issues. The 200-4R transmission is the weak point under increased boost.