With fewer than 1,000 miles on the clock, Kevin Helmintoller's Z laid down 558.22 rwhp and 524.86 rwtq at Seffner, Florida-based Corvette tuner AntiVenom (www.antivenomefi.com). A pair of back-up runs delivered power readings within 7 horses; torque, meanwhile, climbed to a high reading of 541.19 on the third pull. Using a 15 percent correction factor yields best-of-day flywheel readings of 656.73 and 636.69, respectively--easily eclipsing the factory numbers of 638/604.