Here's an update.

I installed a new aux fan switch yesterday. There didn't seem to be any changes in my temperature.

Recall, I had two "clean bills of cooling system health" from two radiator shops, based on their letting the car run for about 20 min and feeling for fan airflow and squeezing hoses (i.e. they didn't do any tests). It may be my system is fine. Unfortunately, in my memory I was idling hot at a cooler temp. Word to the wise: if your system seems to be doing fine, WRITE DOWN some temp readings under various conditions (heavy traffic, AC on; freeway, etc.). I frankly cannot recall for certain WHAT my system was doing "before."

I have new plugs, so will be taking them out and inspecting. I will do a compression test at that time. I haven't done a block test yet as I've been loathe to spend $50 bucks on a tester. I would like to verify that I don't have any kind of head gasket leaks. Other than that, I may need to go on a 50 mile + drive to see if I'm okay. The car seems to handle 15 plus mile drives in Palm Springs 105F plus heat okay at this point.

TMAllison,

I currently have 10/30. I'll go ahead and put in 10/40 at my next oil change, which aint too far away.

__________________
Love driving my '77 450 SEL!
124,000 miles