Hard Starting Hot Big Block

Tests have been letting the car idle with the hood shut for 20-30 min (been raining) which get the coolant up to 190. Voltage while running 13.2-13.6. Voltage when attempting the hot start is 12.8-13.1.
Running Voltage should be around 14.5. 2 1/2 volts over battery voltage. Possibly check your alternator, regulator