Wally you got a good 180 thermostat? Are you running pcv? These motors have to run hot and a route has to exist for the vapors from cold combustion and just like you mentioned temperature changes cold iron and warm moist air. If you have the road draft it has to be clean, and some air movement through rocker cover vents or vented cap to assure air flow. I'm converting my trucks over to pcv for this reason and fuel economy as I find the parts.
