I don't disagree that higher operating temperatures would be better. I haven't been able to figure out how to increase the water and
oil temps from the values shown in my initial post.
Replace 160' thermostat with 180': Not likley to help, since the bypass is limiting the flow to the current level.
Close by-pass and replace thermostat with 180' unit with minimal by-pass: MidOhasp has installed a thermostat that features a restictive by-pass, and he is experiencing temperatures the same as mine under similar air temps.
Restrict the flow of air to the radiator: Dynamic reports this will jeopardize the internal mechanics of the radiator, especially the design features that govern the automatic fans.
Switch from Mobil One 15-50 to a lighter weight
oil. Maybe 10-40?
Don't get me wrong; I appreciate the dialog and you folks are helping. Maybe I have to accept that a 351 stock block, installed in a car capable of supporting a much larger engine, will run cooler than folks expect of a performance tuned engine.
The engine runs fine. The heater isn't much help....