Fastest car I've ever driven was a dirt track stock car, based on a 1980s Chevrolet Monte Carlo. It was running a high-compression 355 ci. (That's either 5.7 or 5.8 liters, for my metric friends) small block V8 with some ungodly level or horsepower...over 500, I'm fairly sure. Belonged to a former employer (owned his own garage and raced the thing on weekends...he's the top driver around here) who let me run the thing up and down the road in front of the shop to test it. I opened it up all right, but didn't hit a very high speed. Sure felt that power, though. Scary and fun.

Fastest speed I've ever driven at was around 105 mph in a 1984 Chevrolet Camaro Berlinetta (my first car).