The cars of the 60's up through the 70's ran 180 thermostats pretty much across the board; at least the few dozen I owned did, along with all of them I repaired for others as I worked in a garage back in school days.
Almost made it a career before I decided I shouldn't - ironically because I loved cars too much, if that makes sense.
Over the years, as manufacturers were forced to literally clean up their act on emissions and fuel economy, the production of engines necessarily became more modern, with advanced metallurgy, casting and machining techniques as well as the advent of computer controls, fuel injection, etc.
Tolerances were tighter; engines ran more efficiently, due in no small part because they could run them hotter, which as has been noted helped naturally with emissions and efficiency.
Bottom line though? Unless you're running an engine made with this modern metallurgy both in castings and internal components, it still makes sense to run them at the temperatures they were "born" with, designed for, manufactured to operate at - and that, once again speaking of the engines of the 60's up through the mid-70's at the least, typically meant 180 degrees.
Don't really care what anyone "says", the factory manuals are the authority on this subject - and the ones I own say 180F.
