[jhandy]

start the car, and turn on the AC. Both fans should start up. more or less together.
Now, turn off the ac and drive, the fans should both turn on at 210-215ish. Mine turn on at 214-215. They both start more or less the same time. The fans are known to go out, so if the AC or high temp does not turn them on, replace.
If you have not done it, take off bumper and mobilize the first radiators. You will be amazed what is in between the two radiators. Buy redline water wetter. 5$ it can only help.
if all seems normal, look to the thermostat or water pump. Pumps seems to go slowly them BAM, overheat.
if you are going to replace the thermostat, might as well get the low temp one from flat6inovations. and if you are going that far, take off the pump and look at the cheap impeller, spin the bearings, replace it if concerned.
And if you are going through all of that, might as well change the fluid. Texaco extended or OEM fluid are great.

How hot does it get?