Ford tests cars by holding them on the limiter for 15 minutes. The factory limiter cuts fuel so fast that there is not enough fuel energy to do any damage. The only thing that is not good is the torsional stress the motor is under by quickly revving, then stopping, then revving, etc.
But you motor, while it has low miles IS 11 years old - the metal in the valve spings may be weak, the rockers may be weak and lifters may be going. The ticking could be any of that.