I'm in the process of re-sealing my 85 5mge, 20 year old rubber gets too dried out and causes leaks! Any way the one thing I forgot to get was a thermostat. I go online and look at two different auto parts stores and see that I can get one at 160 degrees, 180 degrees, 192 degrees, and 195 degrees. I live in the Midwest where the temps can get very cold and pretty hot. I can't read the temp on the one I have, but think I'm going with the 192. My book says to use 187 - 194 degrees. Now my big question is...what the heck is a reverse poppet?