The stock head bolts are torque to yield (which means after a certain torque they stretch) and have designated stretch length limit of 132. 1mm. or 5. 200 in. max. If it was me, I'd take them out one at a time and measure them to see if they are in spec. The proper way to torque by the factory service manual is to start in the center and work your way out to each end. Torque to 59 ft. lbs all the way around and then go to 77 ft. lbs, then one more time to 77ft. lbs. plus a 1/4 turn or 90*.