Tighten enough to take the play out of the rocker/pushrod to begin with. Then tighten when hot and running by giving it an additional 3/4 turn. If it still has a noise then tighten enough to remove it.
Get yourself a Repair Manual or Motors Manual, available online at many of the normal vendors, public library or Amazon.
Do you know for certain that this block is one with oiling galleries for the lifters? If not then it won't work with hydraulic lifters.
