1gm winterizing

[frankfurder]

In the middle of an article cold spell I am asking a question that I should know the answer to!
My 1gm has a drain for the cylinder head. I ran an antifreeze mix thru the cold engine (running but not hot) and then drained the cylinder head.

My question is about the thermostat, does it open to let cooling water bypass the cylinder head when the water temp gets hot, and allows cooler water to circulate in the cylinder head initially, OR does the thermostat bypass the cylinder head with cooling water when cool and run water thru the cylinder head when the water reaches operational temp?

I think the cool water runs thru the cylinder head and hot water gets bypassed to the exhaust elbow to keep the head from overheating?

I have read that removing the thermostat will allow cooler water to circulate thru the block and cylinder head.

Doesn’t really matter at this point , and the boat is in the 50 degree lake water anyway, just looking for input, thanks!