After installing the thickest GM head gasket available, we tightened the 18 head studs per side to 125 ft-lb. This was difficult because we had to use a short torque wrench. We also tightened the four bolts that run along the top of the head to 25 ft-lb. The tightening sequence required progressively torquing the nuts in a special order and then backing them off three times in order to stretch the stud. We started with the lower middle stud, then the upper middle stud, and then a clockwise rotation going from the center out. The little bolts were tightened last, and again we went from the middle to the outer. While doing this it was important to check and make sure the studs did not back themselves out.