160 degree thermostats went out of style back when alcohol-based antifreeze quit being manufactured. A 180 would make the alcohol boil away. The trick to dealing with 200+ degree coolant temps is a pressure cap. Every pound of pressure on a cooling system raises the boiling point 3 degrees, so a 7# cap will keep the coolant from boiling up to 233 degrees. A 14# cap takes the boiling point up to 254- - - - -way above anything a good condition stovebolt engine with a good radiator should ever see. Be sure the heater core you install is rated for pressures equal to or above the cap pressure. A new aluminum radiator should be able to handle 20 PSI or a little more.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!