[Don]

Mentioned in other articles, the speculation that the ZR1 engine actually could be rated higher in HP etc, but Marketing wanted to leave room for future published numbers w/o incurring additional costs. Just enough to stay competitive or ahead of the other higher priced sports cars.

"GM expects the Corvette ZR1 to be the most fuel-efficient 600-horsepower-plus car on the market, which isn't an outlandish statement considering the near-single-digit fuel economy numbers posted by the likes of the near-single-digit fuel economy numbers posted by the likes of the Lamborghini Murcielago LP640 and others "

http://www.motortrend.com/features/a...zr1_horsepower

Probably minimal impact to the gas mileage standard considering the number of ZR1s that would be sold.