What should be my temp?

The stat sets the minimum coolant temperature. The rest of the cooling system, sets the maximum temp. If the fans cannot pull enough air through the rad at idle then the temp will rise and rise and rise and then the rad cap will finally blow off, releasing the pressure, and then it starts all over.
This does not usually happen over 30mph, cuz ram air thru the rad is usually sufficient to help the rad shed heat.
Of course the pump has to be able to move the cooled water thru the engine.

If you are asking what is a desirable minimum water temp to run, I think 205*F is a good number. Engines can and will make more power at a lower temp , but they will also wear out faster at that lower temp. Some say 195*or 185* is a reasonable compromise. My philosophy is that if you can spin the tires all the way thru first gear, you already have more power than the chassis can handle, so, how about giving up some power for long life. I have been running 205 since 1999 AND blowing the tires off to well past 50 or 60 mph.I call that a good compromise.
I run fresh cold air into the carb.
If your engine is sucking in hot underhood air, you may have to run a lower minimum temp to keep the engine out of detonation. Avoiding detonation is priority one.
A high idle rpm creates a lot of underhood heat.You really need to get that lowered. I run a 276/286/110 cam, and my idle is 750 or less. It is a stick car, and I can pull the idle down to 650 or less with the clutch.I only idle it at 750 to ensure lots of oil is circulating.I'm not impressed with a lumpy idle.
If you haven't already set the T-port sync, this should be at the top of your to-do list.