why do you seek to make it run colder? if you're having overheating problems, the thermostat is not the fix - if all is good, it should stay about 160 with a 160 stat, but as Tim points out, there is a range of temp they operate at, it isn't a "snap open/stay open" situation .... and as I said, the exact temp it runs at depends on the condition of everything, I've always found the 235's to run colder than is healthy for them if you let'em, but the engine was designed to work best and last longest at temps above 160, otherwise they can sludge up faster, require more frequent tune-ups and use more gas
Bill
