No luck. The original temp sending unit failed and both units I replaced it with are reading hot. Before the original sending unit failed, it was reading cool to normal during regular use. The only thing I've changed since then are the plugs and points.
If I have a resistance chart for the sending unit, I can take a measurement to determine if it's the coolant gauge on the dashboard or if the car is actually overheating. I ran the car until the temperature gauge read normal with the cap off and stuck a thermometer in the radiator and it read normal.
I'm stumped. I'm going to see if the store has a thermal sensor I can rent.