Virginia is not that hot, near sea level and we dont have mountains, SO I dont run the tank under pressure, hate pressure in radiators at least factory ratings. My Ram 1500, durango, and 73 440 - 6pac have lower temp radiator thermostats and 7 pound caps.
Only had boiling one issue at the dragon on the top of the mountain for a Brief time. Pressure serves to make radiator and things like heaters and intercoolers ACCORDIAN every heating and cooling cycle. Oh yeah, I use at least 50 % antifreeze to raise the boiling point.
Enjoy, W
DY