Just as a reference, my cammer runs at 200° while under way on 90° days both in town and on the freeway. Stopped at a light it will clime to 210° before getting under way. Idling in say a slow fast food line it will climb to 225° without overheating or pre-detonation. I have seen as high as 230° with no problems.

This is with a 190° stat, 4 blade fan, no upper or lower baffles and the stock 3 core rad from my conv when I upgraded to a 4 core. The rad is the only upgrade from a 2 core. All the other items are stock.

Just remember all; the boiling point of 50/50 coolant/water is much higher than water under pressure. If your car is puking up coolant at idle in temps above 70° I'd say you have some problems to solve.