Temperature is OK now.This morning I got up at 0600 hrs ,redrained the rad, etc and changed the aftermarket thermostat that I had installed last week (Motorad brand) .I put in a Ford Motocraft thermostat, added new antifreeze, slowly...started up the engine until it got to operating temperature and took off down the road for a few miles.
The temp gauge needle stayed down by the 'N' where it had been before the problem started.
Thanks, all for your thoughts.
Good luck with your cooling systems.
Roger
