It’s an easy answer. In F1 they put blowers into the air intakes as soon as the car returns to the pit/garage. Nascar needs to develop a blower that will attach to the grill and blow 45 mph air through the radiator. Not cooled air, just outside air. Cooling down on the track should be prohibited and cooling down with water hoses is too complicated and has a potential for cheating.
They only have a 2 x 24” grille area on the front, that would get the radiator but not do much for engine itself.
They already have a quick connect cooling cart they can use but the connector is under the hood- Nutscar says no under hood action.
I see a simple fix- MOVE the connector to inside the driver compartment and reach in the window to plug it in.