Why is the Corvette ZR1 slower in the 1/4 mile and top speed than the Ford GT even

though it has more power? What makes the Corvette ZR1 slower in the 1/4 mile than the Ford GT even though the ZR1 has almost 100 more horsepower?
The other thing is that the ZR1 has 160hp more than the ancient Ferrari F40, but has about the same top speed.
Why is the Corvette SOOOOO far behind cars such as the Enzo Ferrari and Mclaren F1 in 1/4 mile and top speed even though on Paper it should have similar numbers.
A Mclaren F1 can do 241mph even though it has less power than a Corvette ZR1, and an Enzo Ferrari can do almost 222 mph
http://www.need4speed.ws/top-speed/Fabio_Enzo_356/Ferrari-Enzo-356-kmh.html, but the Corvette ZR1 can BARELY break 200 if that.
Sorry, here's the top speed for the Enzo Ferrari, almost 222 MPH.
http://www.need4speed.ws/top-speed/Fabio_Enzo_356/Ferrari-Enzo-356-kmh.html