make sure the head bolt holes are clear of any liquid or you will be wasting your time and money due to hydrolocking the bolt. then 30Nm plus two lots of 70-80 dergrees turn on the breaker bar. then warm the engine for 20 to 30 mins then slacken the bolts off and re torque to 30Nm and then 130ish degress. this process will stretch the bolts once then torque down properly for a second time. when i did mine i went from the 12 oclock position and the tightened to the 5 oclock position this then allows for a bit of play in the bar and socket. it may feel like the bolt will break but they wont.