What is the top speed a car can go?

buggati veryon goes 407kmh max and it is record.

That's the current record for an unmodified production vehicle, Top fuel dragsters and funny cars currently reach speeds around 330 mph (531 kph) and the world land speed record for a wheeled vehicle is 763.035 mph (1227.986 kph).

There is no real answer to the question because the top speed of a vehicle is determined primarily by power output, aerodynamics, wind resistance and weight, and that varies with every vehicle and varies every time you drive it.