No Flames (sorbs :wave: ) but leave the Thermostat alone unless you are building a dedicated 1/4 mile car (which I doubt). First of all the thermostat's rating is only the temperature that it opens, allowing full flow of coolant. So a 160 degree stat will open sooner, but the fan still won't turn on at that low a temperature; so you might run a little cooler on the highway where you have airflow, but not around town in stop and go driving.
Second; if you modify the fan to get it to turn on sooner, you have now done nothing more than triumphantly thrown out 40 years of automotive technology and engineering advancements, and reverted right back to 1966 when lots of cars ran 160 degree thermostats. A modern car is designed to run normally at 200 - 230 degrees; it's more efficient, better for fuel economy, and will allow the engine to burn off condensation in the oil for longer engine life. The whole engine management system is designed around these operating temperatures; you can't alter one thing without affecting the entire system.
Do yourself a favor and leave the correct thermostat in there and go enjoy your car!
If you decide to do it anyway, take the old thermostat in to a good parts store (not a "McParts" store like Autozone, but rather a real parts store, i.e. NAPA or similar) and a good parts guy (or girl) can look it up by the dimensions even if it's not listed by application yet.