If you are running original set-up (voltage regulator not imbedded in alternator) and a 100-amp alternator you should be reading 13.5 to 14.5 volts with a load on the system. 16 is too high, for sure. Things will start to pop after a while (bulbs/fuses/etc), and drive you nuts tracking them down. Replace the regulator again (pretty cheap piece) and look into a new 100-amp alternator as well (also pretty cheap, even when chromed).