A few years ago I mesured some temperatures on my 73 Challenger with a 160 deg F thermostat. All temperature were measured with a thermocouple. Below were the temps:

440 Stock Engine
All temperatures taken at idle, in park, with engine warmed up, 7 blade 216 HD clutch fan, A/C on Max Cool position (except where noted, and in shade.

Temperatures on Engine Cooling

Ambient Air Temp 86 deg F
Condenser Coil leaving Air Temp 108 deg F (air entering radiator)
Radiator Leaving Air Temp 138 deg F
Water Temp Entering Radiator 166 deg F
Water Temp Leaving Radiator 157 deg F


Temperatures on Air Conditioning System

Refrigerant Temp Entering Condenser 149 deg F
Refrigerant Temp Leaving Condenser 116 deg F
Refrigerant Suction Temp Leaving Evap 35 deg F
Air Temperature Leaving Vents 46 deg F Max Cool
Air Temperature Leaving Vents 62 deg F Normal Cool

Just thought I would throw this out here if anyone wanted to see some readings to use for comparision. Also, you might want to check the fan to crank pulley ratio as was mentioned.
Ron