One person has an issue with an electric water pump and it becomes folklore!
50 cubic feet/min = 375 gal/min, unless you are towing a water bowser no pump you can fit in your Pantera will deliver that!
Overheating is typically in traffic with low to no flow over the radiator and engine idling i.e. mechanical pump at slow rpm. This is where an electric booster pump coupled with a PWM controller is a real benefit. At highway speeds the combination of higher RPM and airflow over the radiator should not lead to overheating, or you have other issues.
I did exactly what Peter is proposing on a GT40 stripped out the guts of a mechanical water pump welded over the shaft hole and installed an electric pump to eliminate the engine intrusion into the cabin. But personally I prefer the combination of mechanical with an electric booster and Davies Craig booster is a flow through pump so ideal for that application.