OK to finish this out--I carved away at the fan mounts, I moved the fan switch probe to the upper left hand corner of the radiator where coolant enters from the head, I flushed it again, and I installed the 160 degree thermostat. I checked the dash temp gauge sender spot with a pointer thermometer, and it is accurate. I had pushed the distributor out by 180 degrees when I pushed the new cam into the motor from the front, so the timing was way off. I timed it correctly off of plug wire #4, and trimmed the idle mix screw (downdraft Weber), and it runs pretty nicely now. The car now spends most of its time between 185 and 195, and never gets above 195. The fan switches on at around 180, and keeps the car cool at slow speeds. So I think I have solved the cooling problem. Hooray and thanks for the input everyone.