Thanks for all the comments. My concern was that with the 180 thermo, the oil pressure at idle was almost down on the peg, and the temp gauge is just below the midpoint. I'm guessing that's about 180 degrees give or take.
However, with the 160 installed and a hot engine, the temp gauge shows a definite drop in coolant temperature, and the idle oil pressure goes up to about 7-8 lb.
Also decided to do an oil change from straight 30W to a 15W 40, and the pressure went up a bit more - about 10.
So, I am satisfied, and I think the 160 will be fine. BTW, I see no difference whatsoever in engine performance regardless of the thermostat or oil viscosity. I think I just wanted some peace of mind. Thanks again!
