When you filled the cooling system up did you run it with out the cap on and did you top it off once you see the t-stat opened ? if you just filled it up and put the rad cap on it will be low on coolant when the t-stat did open causing you to have air in the system and building up temmedous presure , just as you described . remember the spring on the t-stat sits in the block .

I cried because I could wheelie then I met someone without a motorcycle