Oil Temps, Relationship of temp to rpm & speed Options

[ThinAir]

Today I took the teener from Flagstaff to Sedona. A change in elevation from 7,000 ft to 4,500 ft and back again. Morning temperatures at 7,000 ft were probably about 40 and temps at noon when I made the climb back to Flagstaff were probably about 70 in Sedona.

My car is a 2.0L 1973 with stock fuel injection, running 87 octane unleaded fuel. I've got the stock center console fuel temp gauge.

On the way to Sedona this morning I took the interstate at 75 mph (about 3400 rpm) and the oil temp gauge had the needle right over the T where the vertical & horizontal strokes cross.

On the way back to Flagstaff I drove through Oak Creek Canyon, which is 40 mph max, but is still about 3400 rpm in 3rd gear. After about 1/2 hour at that speed the oil temp gauge had the needle straight up between the E & M. As I climbed the switchbacks in 2nd gear (20 mph, but still about 3400 rpm) the temp climbed to where the needle split the M down the middle.

Once I was back on top of the canyon, at 7,000 feet, it was back to 55 mph in 4th gear (again about 3400 rpm) and the temp started coming back down until it got down to about the middle of the E.

So... do these readings sound right for the conditions? The thing that struck me about it is that the oil temperature seems to be more related to speed than rpms. Is this what you would expect, or does this indicate that there is a problem with my cooling system?