If it's cold weather(definition of cold ?) 180 is the way to go but in hot weather...85 on up....I run a 160 as it will heat quickly to 160...open and allow the engine to "potentially" run cooler than a 180. Old cars need to run cool...unlike the new cars today that are designed for higher temps. My silverado runs a steady 210 when warm..I wouldn't run My Bee very long at 210. AND as far as burning bad stuff off...would Your finger be hurt any less in a vat of 180 oil or 160 oil ?

In the 50's/60's we'd run no thermostat in summer. Why...keep the old iron cool...High temps...210 plus is not good...I've run a 160 for decades and I'll wager I get more miles out of a block than higher temp stats. My experience of driving for over 45 years.

Note...not to scare you but a 180 in a car with a good cooling system will NOT hurt anything..it's just with a 180...engines tend to run 190 plus..then cool..then heat...where a 160 will keep them under 180 and that's what I prefer