Interesting observations, David. I got a few questions/remarks for you:

1) head temp was the same both ways, even though you had tail wind and
drove 60-65 one way and had head wind, but drove 65-70 the other way. Dave
Kautz, David Schwarze, and I had a little discussion on temperatures some
time ago. It seems that your findings confirm that the flaps-moving
thermostat is doing its work, since it was able to compensate for the
extra load on the engine/heads.

2) you suspect that the oil pressure gauge is giving false readings. Did
you by any chance use teflon tape when installing the sender? If this is
the case, then your sender is not correctly grounded. Also, do you have a
dual sender or are still using the stock oil pressure sender for the dash
light by means of a T? If you have a dual sender only, then it might be
the gauge, and not the sender, after all, that is defective.

Sami

-- 
Sami ('75 Westf.)
dakhlia@wuecona.wustl.edu