I know with 2000 blazer I put in a 180 and it did not seem to idle high at all, after ECU tune was getting 18mpg in town up from 16. On my CC I am not sure if it has a 180 or not. I have not driven it really in like 3 weeks because it been nice and have been using the bike. I do know my ultra gauge does say it gets warmed up all the way, it has a open/closed loop icon.

 

my dads 4.3 Likes to idle high when its not at temp. Around 800 900ish I tried this with an 180 stat. My blazer always had an 195 stat

 

I have a 195 stat in mine. Even when its nearing 100 degrees, with 80% humidity, and with the ac on, the temp gauge never exceeds the 210 mark. Normally it shows one or two little hashes under the 210 mark.