I have read the procedure for tightening the 12mm stretch to yield head bolts in the Haynes and Bentley manuals. Both give a base torque, the instruct that an additional turn of 180 be given to the bolts. Man, I could manage a 90, but not 180. I'm used to head bolt torques of 105-120 on US V8s, but trying for that 180 felt like I was gonna twist the bolt off.
How do you folks do this? Was I too cautious?