Tony, it's a procedure, not a torque spec, on your engine.

With the engine warm and idling slow, you want to slowly loosen each rocker until it clicks, them slowly tighten it until it stops clicking. It's best to take your time and go over the entire engine a couple of times to verify you are at "zero" lash.
After you are satisfied you are at zero the next step is to set the preload, it can be as loose as 1/8 turn to as tight as 1 turn.
I normally shoot for 1/4 turn. I stop the engine and give the 1/4 turn and then restart the engine after a few minutes. You can give the 1/4 turn with the engine running but the engine well miss as each nut is tightened. The lifter has to absorb the 1/4 turn and will often stall as it takes some time for the hydraulic lifter to balance against valve spring pressure.
This can be a messy operation so you might make a cardboard shield to direct the splashing oil back down in to the cylinder head rather than all over. You will want to plug the PCV hose as it will be a vacuum leak and this could cause the engine to run erratic or stall.

GOOD LUCK!!

Thanks
Randy

PS: Another thing to check on inline 6's are the intake manifold bolts, they are often loose and this can sometimes cause erratic idle.

-- Edited by GLHS60 on Wednesday 18th of June 2014 02:42:25 PM

-- Edited by GLHS60 on Wednesday 18th of June 2014 02:44:52 PM