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by Steve Temple  More from Author

Creating a Supercar from a C5 Corvette

For years GM designers have lofted a variety of plans for future Corvettes, considering everything from a twin-turbo setup to even a Wankel rotary in an effort create something new. Truth be told, though, a Corvette will likely always be some variant of a V-8 mounted in the front. There’s just too much historical momentum for the GM battleship to alter its course in a radically different direction.

Not so with Factory Five Racing. Unfettered by the typical constraints of a large corporation, this comparatively small company, arguably the most successful Cobra replicator in the United States, can turn on a dime. And that’s just what it did in creating the GTM supercar, armed with a Corvette engine that’s—get this—mounted amidships (the initials stand for “Grand Touring Midengine”).

While this driveline configuration would be near heresy in a conventional Corvette, it’s ideal for an innovative and affordable exotic that uses all-American components (except for a Porsche 911’s G50 transaxle, but U.S.-built units are under consideration as well). After all, any Corvette enthusiast worth his salt knows the value of C5 components. Even a trashed Vette is a treasure, a Phoenix ready to rise from the ashes. And we’ve found just the place to put those prized pieces.

This repurposing of proven performance parts is hardly something new to Factory Five. Since the 1990s, the company had been known for building clones of Shelby’s ever-popular snake out of 5.0 Mustang. (Note, however, that the ladder frame on the Cobra and the GTM’s tubular spaceframe are custom-designed by Factory Five, so these cars aren’t simply rebodies.)

Why the sudden shift from Ford to GM, and from a replica to an original design? Factory Five’s David Smith notes two main reasons: “The number of GM performance enthusiasts is a much larger market,” he points out. “And I didn’t want to make another replica.”

Developing and marketing custom design is a high-wire act, though, because there’s no “borrowed interest” factor inherent in imitating the body lines of, say, a Ford GT40 or Lamborghini. But Factory Five has one big point in its favor: a loyal and enthusiastic customer base. Indeed, Smith points out that orders GTM production are currently booked ahead for a year and a half, nearly all to repeat customers willing to make the jump from Ford-based Cobra replica to a Corvette-derived supercar.

Gary Cheney is a prime case in point. A building contractor by day, at night he builds Factory Five cars. Lots of ‘em. He was one of Factory Five’s first Cobra customers, and at last count, he’s bolted up four FFR Spec Racers, two street Cobras, and two Daytona coupes.

While strolling the aisles at the SEMA show with David Smith a few years ago, he began needling him about developing a Corvette-powered supercar. Told him that if he built it, he’d buy it. Smith was already thinking along those lines, and forged ahead.

We visited Factory Five a few years ago when the car was still under development, and Smith  allowed us a sneak peek into the company skunk works. Countless hours of shaping went into the body, which was also wind-tunnel-tested (rarely done in the specialty car world). “That was really expensive,” Smith admits, shaking his head. “It costs $2000 per hour, and it took us two days.”

But the result is a shape that’s not only alluring, but also totally functional. As a vivid illustration, recall that early versions of the GT40 had a disturbing tendency to literally lift the nose off the ground at high speed, so much so that it would only track in a straight line. By comparions, the GTM registers 320 pounds of downforce at 150 mph, Smith claims.

“Above all, we want our GTM to be safe to drive at high speed,” he emphasizes. We can vouch for that, having manned the wheel of Smith’s personal racecar, fitted with a 400hp LS6 engine from a 2004 Z06 Corvette. It goes ballistic in a snap, launching from 0-60 mph in 3.2 seconds, and winding out to well over 160 mph in Top Gear.

At speed, the steering is remarkably light and sure, the chassis tight and stable. We whipped through the slalom and it felt like the car was tethered to the apexes. Yet on a turning circle (it’ll pull 1.05g on a skidpad, by the way), it smoothly transitions to a forgiving understeer near the limit, rather than trying to swap ends like a short-wheelbase Cobra. (One way to compensate in the latter car is to punch the gas and counter with some slip-and-slide drift action, but that requires some deft throttle steering.) Even Smith admits how much easier it is to drive the GTM compared to a Cobra replica.

Driving the GTM, it’s admittedly a bit noisy in the cockpit, since that engine sits right behind the nape of the driver’s neck, but there’s none of that rickety ride you might worry about in some home-built specialty cars. We’ve driven a $90,000 Viper coupe that felt less refined than this GTM.

Speaking of price, what’s the downstroke? The cost of the component package (the “kit” label doesn’t do justice to this supercar) is only $20,000. Dollar amounts for the required Corvette pieces will vary, depending on which model you select and its condition, but any ’99 to ’04 C5 will do just fine, thank you (for a complete car in so-so shape, resale prices start in the low teens). Basically the items required include the engine, exhaust, suspension (minus the leaf springs and shocks), brakes, steering column, radiator, fuel tank, computer, wiring, wheels and tires, along with related hardware.

Of course, that all sounds simple on paper, but the actual build time takes longer than Factory Five’s Cobra, which typically requires about 250 hours of wrenching. Since the GTM is an enclosed coupe and has more than twice as many aluminum pieces, it takes at least 350 hours, Smith estimates, and the total cost of components is about $50,000 (unless you already have a “donor” Vette in your garage).

Cheney took things to another level on his GTM, though, as he’s done on every one of his Factory Five projects. He added all sorts of custom touches on the Lambo-orange paint, interior and finish work. He also included Wilwood six-piston brakes, a carbon-fiber louvers and roof scoop, an APR300 rear wing, Borla mufflers, a Mastershift electronic paddle-shift system, among other items. He estimates total time spent at 1200 hours over a 10-month period, with $85,000 invested. Was all the extra time and money worth it? Well, at the highly competitive SEMA show last year Cheney took home the “Best Domestic” trophy.

Not only that, he can proudly proclaim that he personally built a car that can run circles around exotics costing many times more. And best of all—it has all that superb C5 Corvette stuff underneath the skin.


Factory Five Racing

9 Tow Road                                             

Wareham, MA 02571                                     



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