Dart Running Hot?

Did you put in a new thermostat? I had two. A 180, and a 160.the 180 was checked with a digital thermometer. It opened at 192. The 160 opened at 175. They need to be checked. I used the so called 160. Drilled 1/8 holes in it (4) to prevent trapped air. Put a hose spring in the bottom hose. Built a shroud, since none of the factory shrouds would work with my aluminum radiator. Runs 180 unless stopped for a while.