The 51 cooling system will either have a "zero pressure" cooling system, or possibly a 4 pound pressure cap. Each pound of pressure raises the boiling point of the coolant 3 degrees at sea level, somewhat less at higher altitudes. Adding more cooling system pressure might prevent puking some coolant out, but the system is probably overfilled. It could also cause leaks, especially at the heater core. If the coolant isn't getting to a rolling boil and puking lots of coolant the engine isn't "overheating". A 4 pound cap will raise the boil-over temp to around 220 degrees. If you add a fan shroud, be sure it only covers the fan blades halfway. Fully enclosing a fan inside a shroud can actually reduce the airflow. Electric fans are a joke- - - -how many full-grown airlplanes do you see with electric motors driving the propellers?
Jerry
