My 160 might open at 160 but my temp.doesn't stop there. It stays at 180 when i'm driving around town and if I'm I keep the rpm's over 3,000 it runs at 200. If you put in a 100 deg thermastat in are trucks it would open at 100 but it would increase to 180 or more depending on how your driving.
But what is your reason for running a 160 degree stat, performance, mpg? The reason behind a 195 degree stat is to keep the engine as close to a STABLE operating temp as possible ( around 200 degrees is what is suggested for long life out of a normally driven engine). A engine temp that fluctuates 20 + degrees is not good for a normal engine ( but it depends on your application, ie performance).