[Crazy Horse]

In have recently switched my 83 NA's radiator compressor fan from 3-blade to 6-blade with (almost) outstanding results.

Driving around town, the guage stays around the halfway mark.

I took a long highway trip yesterday. As the day's temperature rose over 95 degrees and I set the car on 70 MPH (with AC on), the gauge rose all of the way up to the 7/8's mark. When I slowed under 55 mph, the gauge goes back to near mid range. Only at steady 70 MPH does it rise to an uncomfortable level.

I have the 83 hose bleeder system, which I think works best. I have bled it properly numerous times. I removed the bellypan and insured that all of the "shark slits" were not dented. I put the bellypan back on. I have a car with only 30,000 miles on it and it looks like it is a month or two off the showroom floor. All hoses are in great shape. I have installed the lower temp fan switch and have new Dextron coolant in the system. Fans are running properly and in the right direction.

Anyone have an idea as to why I am having this high MPH only cooling issue?

The only other thing may be some radiator clogging - is this something that may be problematic at higher speed only?

I get tired of running the heater to save my engine. It is really hot down here in the "Cool Hand Luke" swamps.