Do big tires go faster on a car?

The larger tires would actually go slower, as you would have less revolutions over a distance than the smaller tires.

As far the performance of the vehicle, theoretically, if the rear end gears remained the same, the car would have a higher overall top speed with the larger tires... however, that's before you factor in the higher drag coefficient, decreased power-to-weight ratio caused by the heavier wheels and tires, and also where the engine's power band is.