EDIT: Hotter may, in fact be better if for no other reason than power production. See linked article. https://www.allpar.com/fix/engines/cooling-system-about.html I have read the long "tuning a six pack" post that is adamant about everything that is stated in it, and that includes running a 190 degree thermostat to prevent fuel puddling. My inclination is to go 180 degree, and that "cooler engines are happier". I have a 70 V-code Roadrunner with the ALUMINUM Edelbrock/Chrysler 6bbl intake. Aluminum valley pan gasket has crossover heat passages blocked, TTi headers, manual transmission, 71 440 steel crank, heavy rods. Adding Vintage Air AC system I just bought soon. Live and drive/race in the Deep South. But now is the time to decide, because I am installing a Cold Case radiator and the only way I can think of to thoroughly flush all of the old coolant out of the engine is to run fresh water through the engine with the thermostat removed, otherwise the thermostat will be opening and closing and I can only flush out the radiator, let the engine draw that fluid in, circulate one the temperature rises, stop it, flush radiator again, repeat. So those are my 2 questions. Am I right in thinking that removing the thermostat is the best, most thorough way to flush out all of the old coolant, AND what temperature thermostat should I run, should it, in fact, be the 190 degree recommended or is my intuition right and 180 degrees for a cooler running engine the better choice? Lastly, what brand and part # is the absolute best thermostat to get? Stant?