thermostat

I want to replace the thermostat and housing, do I need to drain the coolant completely or since they are both at the top of the block can I get away with replacement and minimal coolant leakage. I have a full coolant flush along with other fluid replacement scheduled next week and would like...

I have a 185 degree thermostat in my el camino at the moment, when the car is first cold it gets up to almost 200-210 degrees before the thermostat opens up and cools off the engine. Afterwards it acts completely normal. Is this typical behavior or should I replace it?