2000 Impala 3.4L question

I have been fighting the intake manifold issue and recently had another engine put in the car. I monitor the engine via the Torque Pro app on my phone. The car has a 195 degree thermostat and the temp varies between 188 and 206. At what temperature do I need NOT to exceed. I would assume that straight up and down is approximately 200 degrees. Is 210, 220, 230 degrees the upper limit before head gasket damage would occur?

Your cooling fans go on at about 220, so much over that is unusual.