/6 running cool !?

I have a 1971 stock /6 with 145k on the clock. I does have a electronic ignition. my question is it is running at 160 to 170 on the street. I have put in a 190 thermostat. I have an AUX gauge mounted in the top side of the radiator its actually in the fluid not just a cheap probe. Has any one else ran in to this?