Factory Five GTM Supercar - Conversion Factor

Factory Five's Amazing GTM Is A Vette-Based Supercar

Steve Temple Nov 1, 2008 0 Comment(s)
Vemp_0811_09_z Factory_five_GTM_supercar Rear_view 2/12

"Above all, we want our GTM to be safe to drive at high speed," Smith emphasizes. We can vouch for that, having manned the wheel of his personal race car (the stealthy black one shown here), which is fitted with a 400hp LS6 engine from an '04 Z06 and a five-speed G50. It goes ballistic in a blinding blink, rocketing from 0-60 mph in 3.2 seconds. It'll wind out to well over 160 mph in top gear, and the stock Corvette brakes bring the GTM to a clenching halt in only 111 feet from 60 mph. Street tires deliver 1.05 g's on the skidpad.

For the hard-core competitor, even more-impressive performance figures are attainable with an LS7 and a six-speed version of the Porsche trans. (How does 0-60 mph in 3.0 seconds grab you?) However, during extensive testing at the Bondurant School of High Performance Driving, chief instructor Mike McGovern noted that the standard LS6/five-speed setup has a more useable powerband on a road course, as well as an easier shift action.

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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 smoothly transitioned to a forgiving understeer near the limit, rather than trying to swap ends.

The GTM is admittedly a bit noisy in the cockpit-perhaps not surprising given that the engine sits right behind the nape of the driver's neck-but there's none of the rickety ride you might encounter in some home-built specialty cars.

Vemp_0811_10_z Factory_five_GTM_supercar LS6_engine 4/12

So, how much will this level of Vette-powered performance set you back? The basic component package 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-'04 C5 will suffice. Basically, the items required include the engine, exhaust, suspension (minus the leaf springs and shocks), brakes, steering column, radiator, fuel tank, computer, wiring, and wheels and tires, along with related hardware. The G50 transaxle can be had for as low as $2,500 on eBay, if you look hard enough.

Of course, that all might appear simple on paper, but the actual buildup takes at least 350 hours, Smith estimates. Still, that's far less time than those one-off, midengine Corvette concepts mentioned at the outset. Not only that, but the GTM is a real, driveable car that's emissions-exempt in most states. Damn tradition-full speed ahead!


Factory Five Racing
(508) 291-3443




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