Well, as I mentioned in my topic here:
Another overheating thread
there was someone who suggested checking the impeller on the water pump. Indeed, that was the root cause of my problem. Whoda thought that on a car with 500 miles? I'd be curious what the stimulus of the failure is so I don't do it. I suspect is was extremely fast acceleration.
Got a new pump and now solid as a rock at 78*C and that is without the aux fan running. This morning I topped it off after all the air bled out to the baffle plate in the Kirkham tank and there was no overflow in the coke bottle.