Harding also fitted numerous carbon-fiber parts and even went so far as to remove the air-conditioning system. He claims his diet program has trimmed the car’s curb weight to below 3,000 pounds, down from 3,132.
Torque meets the tarmac via HRE 597R wheels (19 × 9.5-inch front, 20 × 12-inch rear) wrapped in Nitto Invo tires on the street, while 18-inch/19-inch HRE C21 wheels and Hoosier R6 tires replace them on the track. The street tires measure 285/30ZR19 and 345/25ZR20, while the racing rubber sizes are 295/30ZR18 and 325/30ZR19. Again, Harding’s experience at Katech, including presiding over and participating in the company’s annual customer race weekend, gave him invaluable insight into what works best when it comes to the optimal rolling stock.
That insight helped direct enhancements in the suspension department, too, including the addition of Moton Clubsport double-adjustable shocks paired with Eibach springs and a set of Pfadt Competition sway bars.
While the drivetrain and suspension modifications are all-business, the exterior and interior mods have as much to do with aesthetics as they do performance. Not surprisingly, most of the exterior items are Katech parts, including the carbon-fiber front splitter, which features an undertray and integrated brake ducts, the carbon-fiber rocker panels and the carbon-fiber rear spoiler. The other major exterior upgrade is an ACP World Challenge carbon-fiber hood. Unpainted to expose the carbon-fiber weave, the hood is carefully clear-coated to protect it and give a suitably rich appearance.
Inside, the Z06 takes on a more luxurious, exotic-car feel, thanks to the application of suede-like Alcantara material on the A-pillars, visors, headliner and kick panels. That’s complemented with Caravaggio leather trim (black with red stitching) on the shifter boot, shift knob, parking-brake boot, parking-brake handle and center-console lid. The thick, flat-bottom steering wheel is a Caravaggio item, too.
Ahead of the shifter, affixed just below the radio, is a simple label that reads: “Put Brain in Gear.” Inspired by retired SCCA racer and friend Jim Painter, Harding installed it to help ensure he’s focused on what he’s doing, especially before a few hot laps at a track day.
Though our time behind the wheel was extremely limited, it didn’t take long to be impressed with Harding’s creation. The engine barks to life with authority and settles into an appropriately aggressive idle, with the high-compression 427 kicking out an anxious, “let’s go now” tempo. The engine revs quickly, with immediate throttle response. There’s no delay in the power delivery nor is there suddenly a big spike in output, which can happen with forced-induction engines when the boost comes on. This V8 is linear, predictable and very strong.
We were surprised by the civility of Harding’s Z06 on the street. To be sure, the racing-derived suspension components, not to mention tires with minimal sidewall profiles, create a stiff ride. On the worst stretches of disintegrating pavement around metro Detroit, the ride can be a little jarring, but not prohibitively so. Explains Harding, “Drawing on the experience of the Katech staff has made this car comfortable and efficient on the street, where it gets up to 25 mpg on gasoline and around 20 mpg on E85, and very competitive on the track. I couldn’t ask for more.”
We’ve heard such sentiments from owners before, does he really mean it? “People ask me ‘What’s next, a supercharger or turbo?’” says Harding. “I’m very happy with the power-to-weight ratio that the car has now, and I’m a big fan of naturally aspirated power. A 650-horsepower naturally aspirated engine in a sub-3,000-pound car is a wonderful thing.”
Every job has its perks. Some more than others.