What is the top speeds for a muscle car?

It depends on the car and the equipment used to drive it.

Most muscle cars lack a governor or a speed-control device, which allows the car to reach its max speed potential. The typical top speed of a muscle car during their prime era, was around 130-135mph. This is all the engine could push the car with the stock transmission without over-revving and damaging the motor. The cars were not meant for top speed as much as they were made for quickness and throttle response.