I have a 180* drilled t-stat too, except I drilled 4 3/16" holes (I think) but dont quote me on that and in the summer I could run a constent 170-180*. But I dont sugest doing that unless you have a fan on switch or a reprogrammed PCM b/c in traffic it will get warm quick. Now that it is getting colder I had to take it out and replace it with a 195*, the heat was just not warm enough. Keep in mind that I am on a different platform too. JLAudioEclipse did the same drilled t-stat and his doesn't even hit 180*, and on the highway in the morning he is lucky to hit 150*. But he doesn't have to worry about it because it is on blocks for the winter!