If your Ford's exhaust manifold temperature reaches 800 degrees Fahrenheit, then that is, indeed, considered to be hot. If your car is constantly at 800 degrees, you should consider checking it out to ensure that it does not overheat while on the road. It may overheat due to low oil or water levels. There may also be a clogged radiator or problems with the water pump.
Vadin is a moron. An exhaust manifold can easily go well over 1000 degrees. Think of it this way, an engine functions via small explosions that can be several thousand degrees, the engine block itself is cooled. By time the exhaust gets to the back of the car it is (by law) not at a dangerous temperature. The heat has to go somewhere, and that somewhere is the manifold which is only cooled by the air flowing around it. Most of the heat from an engine is lost in this way. So yes...800 degrees for a taurus is just peachy (I'm guessing you measured it at idle). How is it you have a temperature gauge for high temperatures and yet don't know about flame temperature? Oh, and if you're using an infrared thermometer, note that the result is not entirely accurate unless you can adjust it for the emissivity of the material you are measuring.
