An APS twin-turbo kit uses a pair of Garrett GT3582R ball-bearing turbochargers (61.4mm inlet/82mm outlets on the compressor; 68mm turbine) and mounts them low on the engine. Careful tuning enables the setup to deliver 12 pounds of boost on 100-octane gas and 15 psi when the engine is indulging on top-shelf 105-octane racing fuel. An Apex-i AVC-R boost controller also helps keep a lid on runaway pressure, limiting boost at certain rpm levels and within the various gears of the six-speed box. As we mentioned, the engine combination dyno'd at 1,008 horses and 827 neck-tugging lb-ft of torque.
Torque is sent to an RPM Level 5-prepped Tremec transmission via an Exedy triple-plate carbon clutch and an LG Motorsports carbon-fiber driveshaft. From there, it's channeled to a Quaife differential and stronger 300M-alloy axleshafts. That tremendous twisting power finally meets the road on Pilot Sport-wrapped HRE 19x12.5-inch wheels--with 18x10-inchers and matching Michelin rubber up front.
To absorb the powertrain's output and give the car suitable on-track reflexes, Katech also worked on the suspension. Body roll is reduced to virtually nil with the wide tires and Pfadt Race Engineering's competition "Pfatty" sway-bar kit. Claimed to be up to three times as stiff as the Z06's stock setup, this kit features aluminum arms connected to 4130 chromemoly bars, including a unique straight front bar. Katech also slipped in a set of Pfadt's "pillow blocks"--another term for solid bushings. Some suspension movement is afforded by Moton Club Sport double-adjustable coilovers, while stopping power comes from a Brembo GT system with rotors the size of extra-large pizzas.
"It handles and drives better than my Ford GTs," Gilliland says. That's right, in addition to the 1,000-horse Z06, he owns two of Ford's factory-blown super cars--as well as three more Z06s, a couple of Kenne-Bell-blown Mustang Cobras, and a few other performance cars. None, Gilliland says, compares to the visceral thrill delivered by the turbocharged Corvette.
"It's hard to describe how exciting the performance is," he says. "It pumps up your adrenaline and puts a grin on your face like nothing else. It's incredible."
Wide Body, Trim Cabin
If you've ever visited Katech's shop, you could be forgiven for thinking Chevy offers the Z06 in only one color. Still, Gilliland's example stands out from all the other yellow Katech Vettes with a full complement of exterior enhancements from AC Products and MTI Racing. These include AC's wide-body kit, Magna-Extractor hood, and carbon-fiber front splitter. MTI, meanwhile, supplied one of its carbon-fiber rear spoilers. The swollen fenders nicely cover the wider tires, and the combination of yellow and exposed carbon-fiber weave is accented nicely by the mirror-finish HRE wheels.
Like we mentioned, Gilliland intends to race this thing, and while we're all for getting your money's worth out of a 1,000hp LS7, it's hard to think of those gorgeous finishes getting scuffed up or discolored by heat. The same goes for the well-executed interior, which is trimmed in yellow-and-black leather, with suede-like Alcantara used on the A-pillars and headliner.
Caravaggio racing seats replace the stock Z06 units, and Schroth six-point camlock harnesses are anchored to a harness bar. Additional cabin upgrades include an Alcantara-trimmed three-gauge A-pillar pod that's filled with Defi exhaust-gas temperature and fuel-pressure gauges, as well as an AEM air/fuel-ratio instrument. And to keep tabs on the engine's performance on the track, the gauges are equipped with data-logging capability.
With a car whose performance defies adequate description, it's even harder to sum it up at the close of this story. We've sampled some truly fast, well-built Corvettes in recent years, but Gilliland's is something else entirely. It's an envelope-pushing blend of street-car swagger and race-car capability. Oh, and it has more horsepower than a stable full of mutated Clydesdales drinking from a Red Bull-filled trough.