Hi Bob, Available from Summit 1-800 230 3030, Mr. Gasket part number MRG-4366 is 160 degree, and MRG-4367 is 180 degree. These are good quality, high-flow thermostats. John ----- Original Message ----- From: "Bob Jasinski" > Dear list, > > It has been a very long time since the thermostat in my 300G has been > replaced, maybe 20 years. I seem to remember reading somewhere that the 413 > HP engine used a thermostat that had holes drilled in it to assist in > cooling or water flow. > > So here is my question. Should I obtain a thermostat (180?) from a parts > store and modify it? If so, how? > > Bob J >