<< Well I was finally able to do some checking on the underhood temps. I drove the Z for between 2-3 miles to get the engine up to temp. The outside air temp was in the mid 80's. While driving the temp gauge stayed right around the first quarter marking, maybe one mark up toward the half marking. While idling in my driveway the gauge read right at the one half marking. The engine would not hold a steady idle but slowly had the idle decrease until the engine died. This happened 3-4 times. While the engine was not running the temp gauge would increase until it was between the one half marking and the three quarter marking. This I take to be normal due to heat soak.
Here are the temps I recorded with an infrared gun:
radiator hose at thermostat- 183, bottom radiator hose- 164 >>
The last line above are the only temps that mean anything, and they're normal - don't agonize over all the other external temps - they are what they are, and you can't change them. You don't have a cooling problem, you have a typical fuel percolation problem, aggravated by low E10 fuel boiling points. Insulating your fuel line from the frame to the carb will help, as will an aluminum heat shield that extends under both fuel bowls. E10 fuel boils at 150*F, and at extended idle, the fuel bowls get hotter than that.