George would you take the car to belgium thrash it round a track for 2and half hours then drive back, this is where you wil find your answer
Just an observation George but them rusty coloured stains down the side of your block indicates no anti-freeze, corrosion inhibiter, summer coolant, pump lubricater, call it what you like it needs to be in there dont use the red stuff as it may eat away at your brass heater matrix
what make of head gasket is on your engine
mine is a felpro very high compresssion and reved to 7500 often with no water oosing from the sides