[68chevyfuelie]

Is the water/coolant physically overheating though? Not too sound like a jackass, but you need to start with the basics.

Is the thermostat opening, the upper rad hose getting hot? Is the coolant bubbling and hissing? Rad cap working okay?

I disagree (as an opinion) with needing a shroud for the amount of driving you are talking about. I think you need to determine if the mill is overheating (with no help from the rad) vs. everything working together ('stat open, good coolant flow, etc.).

Also, sometimes overlooked, if it's an A/C truck, if the condenser is plugged, the rad will receieve no airflow. Sometimes those little things when overlooked will bite you in the ass trying to chase a problem.