Brian, I will second what Richard said about keeping your Detroit hot.
It will stay cleaner, be more efficient and last longer if run at 180 instead of 160. While the difference may not be drastic, there is nothing to be gained by running colder thermostats.
For comparison, check some of the modern engines, and find out what temperatures they are running them. In at least some cases, if it wasn't for the pressure cap, they would be boiling!
There has been some push to go to straight propylene glycol, which has a boiling point of something like 370 degrees F. While it has raised the coolant temperature some because of its lower specific heat, the operators have been claiming improved mileage with the increase in temperatures.
While it is expensive, it's supposed to be a one time cost, as the claim is that there is no corrosion and there is no bubble formation from operating too close to the boiling point. So, local overheating is supposed to be a thing of the past.
For what it's worth.
Tom Caffrey
Suncatcher
Ketchikan, Alaska