Well...we solved the "running hot" mystery. I'm very embarrassed to say that the cooling fan rotation was reversed and it was "pushing" rather than "pulling" air through the radiator. Never even considered that...we were looking for something more exotic. Stupid...so obvious...that we never even considered or checked it.
We reversed the rotation of the fan and we go to and stay at 180 ...highway or traffic! Lesson learned...start from the beginning and walk through the basic, common sense functions of the cooling system...9 times out of 10 you'll solve your problem. Thanks for all the valuable imput...


Steve G.
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1942 Chevrolet 1/2-Ton Pickup Truck