Engine runs hot at idle and low speeds

[retro dreamer]

Gentlemen,

My 1975 Chevy 350 small block seems to run hot all the way up to 210*when at low speeds and idle. it seems to stay around there if i keep the heat on but I'm afraid then engine might get damaged.

I've recently changed the oil and oil filter. The thermostat is 180* and is around a year old. I had no such trouble last summer, what could it be?

How do you know when your water pump is shot.

Thanks for helpin a newby tryin o teach himself the ropes,
Perry