[Big Dave]

I put a 203 degree stat on my 7.3 and got a consistent 0.5 MPG increase. Not bad for such a cheap mod.

I also use Evans NPG coolant. This is a nonaqueous mixture of 10% ethylene glycol and 90% propylene glycol. It boils at a temperature over 400 degrees. I use it to defeat the cavitation problem common to 7.3s, but I have always wondered: "What if I could get a 300 degree stat?" One thing for sure: My heater would burn my fingers off. Even on the coldest days I have to temper the heater supply air.