Temp too high ?

It's been a while since I've had to come and seek out the experts here.
My dilemma is the car's temperature while driving about town. Summer time.
What would be considered too high which can possibly cause engine problems, overheat, etc. Thus needing to pull over and shut the car down and wait for it to cool down.
What is considered as "normal" or acceptable temp.
Again thank you all for any replies or info on the matter.

MAPS

P.S. I just realised you might want to know a little about the engine...
340 6bbl
Solid cam 580 lift ( give or take a few degrees) 10 . 5 comp. Headers.
4 speed with 4.10 rear (489 posi track)