The voltage regulator is built into the alternator on all Chevys made from the 1980s to at least 2010. Simply put, the regulator restricts the amount of voltage being sent to the battery. Without a regulator the battery would receive upwards of 30-volts of power while charging, which would quickly damage or destroy your battery. When your Chevy is running, you should get approximately 12.8 to 14.0 volts of power, and there is a quick and easy test to determine if your regulator is over- or under-performing.
Place the red lead of you multimeter onto the positive battery terminal on your car battery. Place the black lead of the multimeter onto your negative battery terminal.