Looking to replace the thermosts on the 96 3.8. Which is the right temp. range, 180 or 195 degrees. Why the 2 different thermostats? Help anyone. Thanks.

Mine is 195 degree for my '96 3.8L.
Looking on Rock Auto's website, they list the 180 degree as "alternate temperature" and 195 as OE temperature.
Best to stay with OE unless some specific reason to change.......
Going cooler is very likely to cause problems with emission and fuel economy as the PCM is setup for the warmer temerature.

If I remember right if you live in a hot area like say AZ or some place like that the lower 185 is better.. Or heavy towing.. I think I also remember taxi's ran lower temp thermo's...

I like to drill a very small bleeder hole in the t'stat body and orient so hole is on top, hole that small won't effect temp rating.

Edit: Thanks wiswind. The orginal had that bleeder, the aftertmarket one didn't, thought I would add it.

The FORD thermostat has that already
http://rides.webshots.com/photo/1340577887011220610MWrvbx

I recently did this job and I bought a fail-safe 192 degree thermostat, I live in new york where temps fluctuate through out the year. These thermostats stay open if they fail instead of close, some prevention there. I also used Felpro's Perma-Dry gasket was thicker than the OEM one. I bought these at Rockauto.com