Thanks guys....I figured so
With the exception of a four year old radiator all the proper goods and maint practices in place. Citrus flushes to new pump, MB Coolant w/ redline, etc. Worked this cooling thing for seven or so years

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I really don't like to run on the "border" of 110. All winter long with ambient temps < 90*F it runs like a cool cucumber @ 80 - 85C.
I think it just getting older with almost 350k. I'm searching for a 70* "Tropical" thermostat for this summer's desert travel and there will be a lot...twice a month....and its just getting warm out there....and at typical 115 F ambient ya just can't roll down the window or ya overheat ones brain lol.
I think the stock set up just can't handle the extra heat x long distance 75 mph.
Wondering if there is an oversized radiator out there or a custom shop anybody knows. Have more room towards the fan for a deeper radiator. Going with a trans cooler too I think.
Thoughts?