The truck ran at 190 degrees until the day it got hot. No mechanical changes were made until after the event. My thought is that some rats nesting that I didn't get out of the old radiator may be inside somewhere clogging something up or a crack in one of the heads occurred. I am running cool now without a thermostat and it is running really well. I will go for the professional back-flush and if the temperature drops off after that I will install a good thermostat. If it doesn't, I will run it until it blows and replace the engine. I need a good excuse to rebuild the original to the drive train 1973 motor anyway.
