Is their web site for Torque settings for Nissan headbolts?

Number system on the head of the bolts is grade of bolt but not all are numbered (don't worry) the service manual the head bolts are torqued in several stages. Blowout the bolt holes.Use a drop of motor oil to the bolt thread Tighten from the middle and sprial outward first torque all to 22#ft then torque all to 43#ft. Then loosen completely next tighten to 22#ft after that either tighten to 47#ft or turn with an angle wrench to 60 degrees. I just tighten to 50#ft as my last torque and spray both sides of the head gasket with Permetex Copper coat. Copper gasket for added sealing and piece of mind. Good luck your next question how to line up the timing marks do not turn the motor with the timing belt off and I reccomend using a Nissan Belt because it has lines dotted on the pengers side cam sprocket and two solid lines for drivers cam sprocket and the dot on the crank sprocket.