2009 Corvette Zr1 Boast An all-new LS9 motor produces 620 horsepower at 6500 rpm and 595 pound-feet of torque at 4000 rpm. Delivering 100 horsepower per liter, the supercharged 6.2-liter V8 is mated to a close-ratio six-speed manual gearbox with a new high-capacity clutch designed for the increased power. The twin-disc 260mm design provides plenty of clamping power, while maintaining a relatively easy clutch action