It was amazing. The grandstands in Pomona, California, were full of spectators who had just seen 290-mph Top Fuelers, 190-mph Pro Stockers, and a whole battery of Comp class machines blaze through the first round of the NHRA Winternationals During the lull between rounds, after the Fuelers have run, it’s standard procedure to walk the pits. On this day, however, most of the fans were waiting in their seats for a few minutes, trying to clear the nitro fumes from their eyes and scrape the “Goodyear freckles” off their bodies when a little truck pulled up to the bleachbox.
It was a pretty truck – an extended cab GMC Sonoma, mostly blue with purple and neon yellow/green graphics, some decals, and a few bars from the rollcage jutting from the rear window, but on, how fast could it be? It’s a truck for cryin’ out loud! After a long, smoky burnout, some eyebrows raised and those spectators who were ready to leave sat back down and decided to give it a look. The truck lit the stage light, the rpms came up on the rev limiter, the lights came down on the tree, and the little blue blur shot off the line, carrying the left front wheel a few yards down the track. It screamed through the traps 9.85 seconds later at 137 mph. The crowd was at first amazed, then completely flabbergasted when they got to the GMC Motorsports trailer in the pits, peeked under the hood, and found only six injectors. That’s right, a naturally aspirated 90-degree V6 propels this beast to single-digit quarter mile times.
The truck we’re talking about is, of course, the one you see on these pages. Built for exhibition purposes only by Vehicle Research and Development in Almont, Michigan, and toured and driven by Don Stringfellow, the Super Coupe (as GMC calls it) started off as a twin to the record-setting 205-mph Bonneville LSR top-speed truck, also driven by Stringfellow. You saw it last in Sport Truck News (December ’91) in LSR-matching black paint with white salt spray graphics at the U.S. Nationals where it turned a 10.01 e.t. Since then, GMC has repainted it in magazine-friendly fright colors and turned up the wick on the motor.
The 120-inch-wheelbase chassis was built using a modified Alston frame kit with Strange and Chassis Engineering components. Strange A-arms and struts are used in front, while the rear suspension consists of a Strange-stuffed, 5.14-geared Ford 9-inch suspended with Chassis Engineering Hardware. Fourteen-inch-wide Firestone slicks get the power to the pavement and JFZ brakes work in conjunction with a hefty parachute to slow the truck from its triple-digit speeds.
The most amazing part of the Super Coupe, however, is the six-cylinder powerplant. The Katech-built engine is the same powerplant used in the LSR truck, but with some recalibration for quarter-mile action. It uses a 90-degree Vortech V6 block, a Moldex crank, Carrillo rods, and Cosworth pistons. A bore and stroke change ups the displacement to 302 cubes, and the compression ratio comes in at a stout 14.3:1. No, they don’t run it on pump gas. Bow-Tie splayed valve heads use Del West titanium valves, actuated by a General Kinetics cam, Isky lifters, Ryan Falconer rocker arms, and Competition Cams springs. The induction system is a trick setup from Kinsler that uses a Delco Electronics GEN III engine management system straight from an Indy car. The result is 569 horsepower at 7200 rpm, and 451 lbs-ft of torque at 6000 rpm. Those are phenomenal numbers for a 302 V6 without forced induction or nitrous.
Hydramatic Motorsports beefed up a 3L80 automatic transmission (which is essentially a TH400) to handle the torque, and used a high-stall converter to get the truck off the line. Stringfellow stirs the gears with a Hurst Quarter Stick shifter.
The drivetrain and chassis are certainly trick, but what first grabs your eyes is the knockout paint and bodywork. The extended cab body is all steel, with the exception of a Dzus-fastened fiberglass hood. If the headlights look funny, that’s because they’re not really headlights, but instead painted covers in the otherwise stock grille. Syclone-style ground effects visually lower the truck. The paint scheme was designed by the GM Design Staff in Warren, Michigan, and executed by Steve Tabor at Lightnen’s Custom. Graphik Concepts in Farmington Hills, Michigan, supplied the decals.
The Super Coupe will be touring the NHRA national event circuit, so when the big boys hit your town, cruise over to the GMC Motorsports trailer in the pits and look for Stringfellow and his V6 missile. And don’t immediately leave the stands between rounds. You never know what you’ll see.