[jhein]

From what you said, it sounds like you're not worried so much about the 197 temp but more worried about the fact it may keep going up until you overheat. If that's the case, just test it. Get it fully heat soaked then return to your driveway and let it sit and see what happens. You may find that it will reach a limit and not overheat.

I don't have AC but here's what my car does. I have a OEM style radiator 180 deg thermostat and a flex fan (not sure of the diameter) and a factory shroud. The motor runs at 180 at all times while moving at any speed. At a stop, it will climb up to about 190 fairly quickly. But, it never goes higher. I almost never have to stop for more than a couple seconds at a stop sign but every now and then there's road work going on and I may have to stop for a couple minutes. The first time I watched my temp climbing up quickly I got a bit nervous. But then once I got moving again it came right down. So anyway, I tested it like I described and it climbs up to maybe 190-195 and just stays there. Doesn't keep climbing. So give it a try and see what happens.

Also, are you running vacuum advance? If so, is it connected to ported or manifold? Manifold will run cooler at idle. Also, depending on your driving conditions, radiator fins can get clogged up with bugs and debris that can affect cooling especially at a stop. Probably not the case with your car but you never know.