Originally, Marty Beaulieu asked Cobra Automotive to build his '67 Shelby GT500 into a clone of Shelby's famous Super Snake, a prototype of a proposed 427-powered GT500 that Shelby himself drove to 170 mph in a high-speed test. But Cobra Automotive founder and president, Curt Vogt, had a better idea. What if, Vogt suggested, they added twin Paxton superchargers to the mix, sort of a Mustang version of the twin-Paxton Cobra that Shelby built for comedian Bill Cosby?
"Curt talked me into it," Marty says. "Good thing, huh?"
You betcha. Even without the superchargers, the engine is an FE masterpiece. Starting with a balanced and blueprinted 427 side-oiler block, Cobra Automotive added ported Dove aluminum, medium-riser FE heads, custom-ground Ultradyne mechanical camshaft, and dual Holley 660-cfm center-shooter carbs on a ported aluminum intake. Naturally aspirated, the big 427 made 583 hp on an engine dyno. Then, it was installed into the Shelby, and the pair of vintage-style Paxtons added five pounds of boost.
"We made an educated guess of 700 hp at the flywheel," Curt tells us. "On a local chassis dyno, it made 613 hp at the rear wheels. Figuring a 15 percent loss through the drivetrain, that comes to 705 hp. We were right on the money!" Cobra Automotive (37 Warehouse Point Rd., Wallingford, CT 06492; 203/284-3863; www.cobraautomotive.com) is a full-service Ford performance center with Ford performance parts, a race shop, an engine room, and a paint/restoration shop, making it the perfect place for the Beaulieu GT500's combination of restoration, modification, and powerful big-block.
The 45,000-mile Shelby, which was originally sold at the fabled Tasca Ford, was stripped to the bare shell for media-blasting, then reassembled restoration style with original Shelby fiberglass, restored stainless trim, and Acapulco Blue paint, hand-rubbed and buffed to a concours shine. The interior was also restored, although the driver-side seat box was relocated for extra leg room.
But, as the Shelby went back together during the three-year process, Cobra Automotive stepped away from total restoration mode by adding performance and durability pieces to complement the power under the hood. The drivetrain consists of a close-ratio Top Loader four-speed with Hurst shifter, Centerforce 11-inch clutch and pressure plate, and a Currie 9-inch rearend fitted with Cobra Automotive tubes, Strange nodular-iron carrier, 3.50:1 gears in a Detroit Locker differential, and 31-spline Moser axles. For sufficient braking, Cobra Automotive utilized its own competition front-disc brakes with 12-inch rotors, Lincoln-type four-piston calipers, and oversized 11x2 ¼-inch competition rear drums.
With over 600 hp making its way to the rear wheels, Cobra Automotive prepared the chassis by stitch-welding the unibody. Then, the company added its own competition lower crossmember and subframe connectors. The suspension was then beefed up with Koni shocks all around, heavy-duty upper and lower control arms, 1-inch front sway bar, Energy Suspension polyurethane bushings, performance rear leaf springs, and Cal-track traction bars. For precise steering, all-new Moog steering pieces were incorporated with a blueprinted Flaming River 16:1 steering box and Cobra Automotive big spindle kit.
A Fuel Safe 16-gallon fuel cell resides in the trunk, while Hooker 2 1/8-inch Competition headers feed into a combination of Dynomax collector mufflers plus Dynomax bullet mufflers with 3 ½-inch side-exiting tips. Wheels are original Shelby 10-spokes mounted with BFGoodrich T/As on the front and sticky drag radials on the rear.
With conservative timing, the twin-blown 427 tools around town on regular pump gas. But when you nail the throttle, as Curt says, "It's 700 hp!" Obviously, Marty Beaulieu's GT500 lives up to Curt's motto: "We're always looking for the opportunity to take the next step into lunacy!"