Depends on your truck.
My 98 is OBDII.
It does not monitor EGT's, nor does it care about ECT.
You can run it up to 1200+F in egt's and scorch past 220F in coolant on the stock PCM hauling up hills. Mountains can be worse, it'll top 1400 easily. Stock
While the engine won't drop dead at first, you cut the life cycles of the engine by over temping them.
The generally accepted sustained values for my truck is 210 ECT and 1100 F egt.
My powertrain is not stock anymore either. The list is far too long to itemize here.
My modified truck manages towing and egt's better than the stock setup. But I've modified my truck for towing, not lots of power.
Here's my interior:
The lower console is a photochop of when I was working out the layout.
IN the upper dash is boost and EGT.
The lower console is lift pump pressure, trans temperature and engine oil temperature.
There are actually only three gauges in the lower console. the 4th gauge spot is where my Devils Own water injection controller is mounted:
That's the closest picture I currently have of it's finished state.
I also built a repeater panel with warning lights controlled by the gauges:
Again, that's a photochop. Closest picture I have to the finished one:
The warning lights tick off a light for items such as EGT (comes on at 1050F) so I don't have to look down to know I'm reaching a limit. Some other ones are low level in my water tank, WIF on my prefilter, over boost, etc....
Lastly, my brake controller which also displays volts:
Currently thinking of places to get IAT, differential temps, transfer case temps, etc into the interior as well.
The touch screen is a back up camera, but it will soon display a car computer which will be hooked up to an OBDII interface. I have a program called "DASHCOMMAND" which will let me create my own guages and display whatever PID I define, as long as my truck supports it.
I fly helicopters for a living, I like to know exactly
what my machines are doing......