[scottj]

Brad,
Good point about the the exhaust glowing. The reason it's glowing is because fuel is burning in the header instead of in the cylinder. Rich is one reason for this, if it's lean it burns before reaching the header. Ignition timing that is retarded from where the engine makes peak power will also cause this, sending EGT to the moon. Exhaust valve timing too early? Same thing.
Also, a more efficient combustion chamber will have lower EGT, but higher cylinder temps. By turning more fuel in to heat in the cylinder, the exhaust temps are cooler. You could see a difference of 200 deg. on EGT for two perfectly jetted engines because of differences in combustion chamber efficiency.

A stoichiometric mixture produces the highest temperature from gasoline, makes the most cylinder pressure, and produces the most power. Going rich or lean from there drops temp, pressure, and power. The lower the exhaust temp is at stoichiometric the more heat is being converted into pressure an thus power and the less fuel is being wasted as heat out the exhaust.

Scott