I have a cooling system test kit that has caps, pressure pump and you can put a test guage into the coolant of the rad thru the cap--highly accurate and i recommend getting one for anyone fooling with this stuff.

Mike--That cross ove r on stock hemi arrangement actually disapates a lot (well some) heat and altho handy for the sensor will be somewhat inconsistent at various vehicle(airflow) speeds and eng rpm for coolant flow---