There is no definate answer to "what temp". What one person thinks is the appropriate temp for your engine to be at may be different than yours because of so many variables.
Fuel, plug, air temp, altitude, humidity, gear ratios, etc.... all have influence on how hot or cool an engine runs.

Your engine will never be too hot if you do not tune it too lean (assuming it is getting adequate air to the heat sink). Basicaly put, if you tune your engine so that it does not have any lean symptoms, and you have it tuned for crisp and clean transition, you will not have a lean run (due to tune).