The GTR we tested is owned by Mike and Michelle Cowan, a Longmont, Colorado, couple who enjoy hearing small-block thunder rattle through long-tube headers and stainless-steel exhaust pipes relieved of their catalytic converters. Even though it's substantially heavier and packs less piston displacement than a factory-built Z06, the GTR matches the Z06's 4.1-second 0-to-60-mph acceleration sprint on the way to an impressive 12.5-second, 121-mph quarter-mile pass. The lowered ride height provides razor-sharp turn-in, and the wide Michelins deliver well over 1 g of cornering grip with a comforting touch of understeer at the limit. The upgraded brake system does a superb job of shedding unwanted momentum on Chrysler's challenging 1.7-mile road course.
While the factory team dithers on C7 development, Nowicki doesn't mind filling the void with his GTR, effectively a C6.5 Corvette armed with take-no-prisoners design and performance.
SLP (Street Legal Performance) founder Ed Hamburger also knows how to squeeze extra oomph out of a small-block V-8. More than thirty years ago, he made his name as the guru of oil pans. His Toms River, New Jersey, plant converted more than 50,000 fourth-generation Pontiac Firebirds and Chevrolet Camaros into street racers for GM. Now that the Camaro is back from the dead, SLP has a sprawling family of models sporting ZL identification to resume the beat. Blame the ZL575 recently loaned to us for the permanent scorch marks adorning several southeastern Michigan neighborhoods.
This Camaro conversion is essentially the fifth-generation Z28 that GM hasn't quite gotten around to releasing. An Eaton supercharger similar to the one fitted to the Corvette ZR1 pumps air at 6 psi into the 6.2-liter LS3, inflating output to 575 hp and 550 lb-ft. Stock engine covers are trimmed and relabeled for this duty, and the blower is fed cold air through a new low-restriction filter assembly. New mufflers and behind-the-axle pipes trumpet motor melody via four-inch exhaust tips. Stiffer springs drop the ride height an inch, and the new tubular antiroll bars are adjustable. Brembo fifteen-inch front rotors and six-piston calipers enhance stopping power.
The exterior guise includes cool twenty-inch redline wheels, a fiberglass hood equipped with a functional scoop, a raised deck-lid spoiler, a prominent SS grille badge, and various stick-on graphics for the hood, front fenders, side gills, and taillamp panel. Inside, the floor mats and headrests receive SS ZL575 logos. A numbered dash plaque, two key fobs, and a car cover are also included. SLP's only major lapse was not replacing the Camaro's steering wheel.