What a difference a small part can make - since I replaced the worn out ball joint linkage of the timing adjustment (and set the timing again) my 1916 T is performing better and does not suffer from overheating anymore. Now it makes hills with 5 - 7 % grade with 25 - 30 mph in high gear and after longer trips on days with more than 20 degrees temperature the radiator just is gurgeling a bit after stopping the engine. Before I had to go down in low and had some hissing steam on even short trips due to an obviously too retarded position of the timer with the lever all the way down.
I am really happy with that 'upgrade' now.
The part that makes the difference: