I have a 2001 Int'l 9900 with a Caterpillar C-12 and straight 10 transmission. When running loaded at 79 or 80K my EGT gauge goes up to around 1100 to 1200degrees while accelerating in 10th gear and stays around 900 to 1000 when running around 63 mph.

RPM's are 1500 at 63 mph with the OD and rears combo that I have. I don't mind the 1500 revs cause it allows me to slow down a little without going back to 9th and allows for a little drag on hills.
The water temps very seldom get to 200 degrees, even on warmer days. Oil temps also stay well in check.

The exhaust numbers just seem high to me, maybe I'm just crazy, or both...