1986 Buick Grand National- A GNX Clone

As much time and effort as ASC McLaren put into designing the GNX, it simply can't compete with the 20 years aftermarket manufacturers and speed shops have put into creating the ultimate Grand National. In this example, Richard Green managed to turn an ordinary stock GN into a 10-second beast worthy of GNX badges.

As a V-8 musclecar fanatic, the Chicago native's love affair with Turbo Buicks didn't take hold until fairly recently when he helped his son purchase a 1987 GN. The more the two of them started scratching that itch for more power, the more Richard began desiring a GN of his own to modify. It just so happened that when he went to purchase a knock detector from Casper's Electronics for his son's GN, owner John Spina said that he was selling an '86 GN. Green couldn't pass up the deal on the 73,000-mile Buford, and at last he had his own toy. The horsepower war raged in the bloodlines as both Richard and his son were dropping ETs like a bad habit. Both GNs were in the 11s before Richard's son sold his GN to purchase a ring for his wife-to-be. It was just as well, though, as his father would need an extra set of hands for the next wave of mods he had in mind.

In its second incarnation, the bolt-on GN was transformed into a wild beast of a GNX clone. Working closely with the guys at Vans & Customs in Bradenton, Fla., the GNX fender flares and vents were applied after a thorough stripping of the original GM black paint. It took three coats of primer, four coats of Sikkens Mercedes Black, three coats of clear, and hours of wet sanding in between coats with 1,000-grit paper (and 2,000-grit on the clear coat) to get the finish just right. The interior was also given the GNX treatment as well, including the official GNX plaque above the glove box, which was purchased by a friend from McLaren. Richard's plaque is a duplicate of a fallen soldier, a GNX totaled in an accident and crushed. This authentic touch is only slightly compromised by the T-tops, B&M Megashifter, Autometer gauges, custom switch panel, and custom 6-point roll cage. Richard said the roll cage took about a month for him to design and fabricate, in order to avoid cutting the interior or straining to maneuver around the door bar during use.

The engine build, on the other hand, required little more than a phone call to Turbo Buick specialists Street Performance in nearby Park Ridge, Ill. The stock block was taken .030 over and billet mains were added to secure the freshened stock crank. The reconditioned stock rods and JE forged pistons would also help ensure a reliable bottom end for the 10-second streetcar. A custom-ground camshaft from COMP Cams, which is now available off-the-shelf, added 224 degrees of duration and .573-inch lift to all of the Ferrea stainless valves with a 112 LSA. Street Performance reworked the stock iron heads for greater port and combustion efficiency, aided by the larger 1.70 intake and 1.50 exhaust valves. A set of T&D 1.5 roller rockers and hardened pushrods also help make use of the fresh atmosphere swallowed by an Accufab 70mm throttle body and modified stock doghouse. An Applied Technology front mount air-to-air intercooler keeps detonation at bay from the 18-20 psi of boost supplied by a Garrett TE45 turbo. At the time in which the motor was built the TE45 was one of the premier street and strip turbos, utilizing a 63mm compressor and T04B P Trim turbine to prevent lag while providing sufficient flow for 10-second power. When exhaust is not spewing out a Turbonetics Racegate, the Jet Hot coated stock manifolds route the recycled gases through a custom 3-inch stainless downpipe and 2.5-inch exhaust with Edelbrock mufflers. A set of Siemens 55-pound low impedance injectors and an Applied Technology dual in-tank fuel pump is required for this serious setup, with a FAST engine management system manning the helm.

Getting the power to the pavement, as they say, has proved a little tricky over the years. While building boost on the line (at the drag strip), the Buford kept pushing through the lights. The first solution was switching to a Stainless Steel Brakes rear disc conversion. While this did improve the braking performance, it failed to accomplish what Green had hoped. However, when transbrakes became available for 200-4Rs he had Jimmy's Transmission in Mundeline build him a Level 10 tranny--problem solved. A Precision Industries 3500-stall, 9-inch converter, in combination with the 10psi/2,500rpm launch off the transbrake, now enables 1.40 short times. Richard's GNX clone also has the benefit of Strange Engineering double adjustable shocks, which were prototypes at the time, and custom billet aluminum lower control arms with polyurethane bushings. For most trips to the track, the 15-inch Centerline Telestars and Nitto drag radials stay put. However, on occasion, Green has been known to strap on a set of 26x10.5 Mickey Thompson slicks. An adjustable rear pinion snubber and a set of airbags help preload the suspension well enough to negate an aftermarket sway bar, despite running a best of 10.52 at 138 mph. Now that's something neither McLaren nor the General himself accomplished!

Data FileCar: 1986 Grand National