Did a super zippy 30 minute thermostat swap last night. There was a 180°F in there, factory calls for 195°F (like this one from Checker Auto Parts ).

My understanding is that higher combustion temperatures, in addition to the downside of increasing NOx emissions will reduce other emissions gases (like HC). (Can anyone point to a book or URL that confirms this?) And the thermostat plays a role in combustion temp as does timing. So that's why I am switching to the factory 195°F t-stat. I've already advanced timing a bit.

I also employed a tip someone shared with me (you can Google this). Drill a small hole (1/8", 3/32", 2mm, etc) in the flange of the thermostat to help in bleeding air out of the system without affecting normal operation of the thermostat.

So that's one baby step of several more left on the path to Vehicle Emissions enlightenment.

Not to mention it puts me a step closer to achieving my goals for a season of four wheeling, fishing, and camping!