I snapped an ARP head stud today while putting the heads back on. I was only at 70 ft-lbs on the torque wrench when it snapped. Never seen that before. Got lucky, the stud came out without any problems so I just need to order some replacements and keep going. Very weird, maybe a defective stud? I've re-used studs in the past multiple times with zero issues. Not sure why this one broke.