Just a thought, do you think it might be a leaking head gasket. Dumping a little exhaust gas into the water jacket at high RPM. Same problem with my 72, cool at idle but hot at highway speeds. But I have a leak in the head gasket that I know about. Good luck. Chuck in Chico

I wouldn't space the fan forward, it's supposed to be half in and half out of the shroud. Also, have you checked your vacuum advance? If it isn't working you will get overheating at cruising speeds. Joe

HAving similar problems w '77 auto pkg. Tried changing thermostat went down to 160 but no really change. once it warms up, creeps betwen 190 and 210 around 210 at speeds 55-70 and 190 around middle city speeds. Don't know if changing your "stat" makes the difference, Im going to check the belt and then the pump... I have new belts and hoses, too new radiator w. prop mix of cool stuff.. Let me know your outcome! Ron in Eagle Pass, Texas

I've noticed that there has been no discussion on aluminum radiators. I know they are expensive but what kind of results have people seen? I've heard nothing but great things about them.

Keep us posted on your progress, overheating is such a common problem that I'm sure many of us are interested in what caused your problem.