introduced the 2009 Corvette ZR1 at the Detroit Auto Show in January, the automaker described the car's supercharged 6.2-liter V8 engine as "targeted at producing at least 100 horsepower per liter, or 620 horsepower, and approximately 595 lb.-ft. of torque." Unlike the car itself, it turns out those estimates were a little bit conservative. Chevrolet has now announced the ZR1 will return with a slightly more staggering 638 horsepower and 604 pound-feet of torque. Leaving little room for doubt, GM calls it "unquestionably" the most powerful automotive production engine it's ever produced. Powerful enough, in fact, to push the ZR1 to 205 mph, as captured in the GM video linked at left. Liberal use of carbon fiber helps lighten the load, as does removal of the dash found on 1990-1995 "ZR-1" models. The company hasn't announced a zero-to-60 mph time, but we won't be surprised if it ends up being closer to three seconds than four. Awed, maybe, but not surprised.