1993 944 overheating problem
 

I just bought a 1983 944 forvery very cheap i drove it around before noticing the heat gauge was all the way up. i stopped the car and put some work into it. new radiator new fans new thermostat, new waterpump and all. There are no leaks at all. After i drive the car about 5 minutes the gauge will go up very very high and about 10 mintes its all the way up and doesnt go any higher. when i step out of the car the radiator sounds like its bubling and if i squeez the top radiator hose it hot and there is very little pressure. Could it be a blown head gasket? i have never had a porsche before and im only 17 please help me out. are there tests i can do to find the problem.