The fastest production racing car as of February of 2014 is the Hennessey Venom GT, which hit 270 miles per hour at the Kennedy Space Center's shuttle strip. The 2014 Guinness land speed record for a production car is held by the Bugatti Veyron Super Sport, at 268 mph.
The reason why the Venom GT does not hold the Guinness record despite being the faster car is that it has been unable to repeat the run down NASA's shuttle strip. Guinness rules require a record-holder to make two runs in opposite directions down the same track in order to receive the title of world's fastest. However, the top speed of 270 miles per hour was independently verified by GPS.
The fastest Formula 1 car in the world is the BAR-Honda 067 Lakeste. It achieved a top speed of 256 miles per hour in 2006. During its single race, the car never achieved over 246 miles per hour; the engineering team had aimed at 248. However, in a subsequent unofficial run on an airstrip near the Bonneville, Calif., track, the car met and exceeded its goal. As of 2014, the current land speed record of any vehicle is held by the ThrustSSC with 763 miles per hour achieved in 1997. Unlike the other vehicles listed here, the ThrustSSC is jet-propelled.