Coolant Temperature

Using an after market gauge monitoring temp on the left head I see consistent readings of 220 degrees just cruising down the road. I would suspect that if I were monitoring water temp at the thermostat housing outside the engine I'd see perhaps 205+ at least. So it sort of depends on where your gauge is measuring the water temperature. A pressurized water system can run with water temps up over 250. I've never boiled off my system pulling some long, steep grades out here in the west.