Like Jay, I have been running 160 degree thermostats "forever", including in the 390 in my old 74 F350 car hauler. I drove that truck for 26 years with the 160 Tstat, sold it 8 years ago, and to the best of my knowledge, it is still is still in use. In all those years, I never had to add any oil between changes, so I have to question the "rapid engine wear" from running "too cool". I have seen many more engines damaged from excess heat than running cooler, and I would much prefer having a 30 or 40 degree safety margin if I got stuck in gridlock for a long border line up, event parking,etc, with my engine at 165-170, then if it was already at 190 or 200. And no one can deny that a cooler running engine makes more power. I think much of this "cool is bad" myth came about from a study years ago concerning engine temps vs wear, which did show very low temps (like cold start up, to about 120 degrees) absolutely did show accelerated wear, but in my opinion, it was showing the wear from cold starts, not so much from lower coolant temps. Once the temp got up much over 140 degrees, the graph line was not much different than 190. I assume hotter coolant makes the oil less likely to sludge up, but how many of us are driving our FEs 10s of thousands of miles per year, and going over 6000 miles or more between oil changes? My F350s 390 rarely saw more than 2000 miles a year, and had a oil change at the beginning of each racing season, and I changed the valve cover gaskets after about 20 years of the 160 Tstat, and the heads and valvetrain were spotlessly clean