Most rockers studs are 50 ft-lbs. For rocker adjustment I always use the firing order method. Put #1 on top dead center. Both valves closed. Adjust both rockers to zero lash and then 3/4 turn preload and tighten down the allen screw. Then turn the engine 90 degrees and adjust #3. Continue through the firing order till done.
Basically zero lash is when the rocker just comes in contact with the valve and pushrod, so there is no free play. Then preload is tightening the stud so the rocker pushes down on the pushrod/lifter just enough to put slight load on the lifter. If you were to leave it at zero lash, the pushrod would basically spring off the end of the lifter when the engine is running. You want that "preload' so the lifter is not in it's fully "open" position when you lock the rocker down.
Hydraulic Lifter/Valve Adjustment
1. Remove the valve covers, and pick a cylinder you are going to set the pre-load on. Only do one cylinder at a time.
2. Rotate the engine in its normal direction of rotation (clockwise) and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder's intake rocker arm.
3. To adjust, back off the intake rocker arm adjusting nut and remove any tension from the push rod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the push rod seat up against the retaining lock, if you give it time to do so.
4. Twist the intake push rod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning of the push rod, you are at "Zero Lash". Turn the adjusting nut down one half to three-quarters of a turn from that point for street applications. Use 1/8 to 1/4 turn for race applications. Lock the adjuster into position. The intake is now adjusted properly.
5. Continue to turn the engine, watching that same intake valve/rocker you just set. It will go to full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.
6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.
There may be some initial valvetrain noise when the engine is first fired up but once oil pressure has stabilized and the engine heats up, it should quiet right down to a normal level.
Remember that some racier camshafts will have a mechanical sound to them and will not be a silent as factory units.