What battery voltages should you see

14.8 V does sounds a bit high, but I am no expert on battery chemistry. My guess is that the 2.2 V above a fully charged battery (12.6 V) does not cause more current flow into it, which would "boil off" the water (convert H2O into H2 and O2 gases). The electro-chemistry must be similar to a diode effect. If you went higher in alternator output, you would start to dissociate the water.

I suspect most voltage regulators are set to control to ~14.3 V. Of course they control to the voltage drop they sense, which is where most A-body owner's problems arise since the sensed voltage is lower than true battery voltage, due to drops in corroded wiring.