Hi Casey, hopper cooled engines Redstone, Changfoids, and just about all the old Antique Hit and Miss engines use evaporation
to cool, the water actually boils in the hopper, so they run at close to 212 degrees. The Lister(oids) circulate coolant like more modern
things cars, farm tractors, trucks and the like. The only downside to hopper cooling, my opinion only, is that you have to babysit the things. During power outages here when I run The Great Walla Walla Xing Dong, I am up and out every hour or two filling the hopper, and just generally checking on things. It is just not a start it and forget it proposition.
Hope this helps.
Ron