Torque to yield headbolts
You need an angle gauge adapter for the wrench you use to tighten the headbolts. First torque each headbolt IN SEQUENCE to 48-55 ft.lbs. Then using the angle gauge adapter tighten each headbolt IN SEQUENCE 90 to 110 degrees farther. It is critical to have the bolts tighten evenly so I wouldn't rely on any other visual method of determining the degrees. I have seen these gauges on ebay inexpensively. Use only new headbolts, they're one time use only. John