Your 30 mph speeds were enough to keep the temperature from rising further even though your engine was creating more heat, but your speed wasn't fast enough to move the temperature back down.
OK... so even a steady 30 mph isn't enough air to do away with the need for a fan?? I always thought that was fast enough, but apparently not!
My temps do not climb at higher speeds, they just don't go down (like yours do). I expect to run just above t-stat temp when doing 60 mph, and that is not what happens, either with the old 26" copper rad or the new 26" aluminum one, and a high-flow stat.
The water pump is slightly underdriven (stock non-a/c pulleys). I'm going to replace the pump with a Flowkooler high-flow unit, and will also then find out what's in there (hope it's not a 6-vane a/c pump, I can't recall).
