1979 ford cortina mk4 - rotrax kit car - overheating issue

[fubar sounds]

Hi, i have recently ish purchased the car above and have been raging it around a fair bit , it has now started to over heat chronically in this good weather,i drive quite are and the minute i hit traffic the temperature gauge shoots up and when it get to warming level it started to choke up lose revs and cut out and not start. Now i v ordered a new fan to strap on , and in the mean time the mechanic removed the thermostat stating as i was not running a heater i did not need it. But now the temperature gauge shoots straight up on a small 5 mile journey and when i arrive i switch off the engine and 5 seconds later there is a boiling noise and about 400 ml of brown rusty water is deposited on he pavement via the over flow expansion box on the side of the rad. Can anyone suggest any helpful ways to improve my situation ?

[Turn7]

Head gasket is my thinking. Get a sniff test done to confirm.