I have spoken with some Chevy-boys (lost souls
) about this. The method that they use is that they adjust the lifters when the engine is running!
They do it like this:
(First of all it is adviced to have an old valve cover that you can use to keep the oil in the engine. You simply chop off the top of the valve cover so that only the side walls are left.)
When the engine is idling, loose the bolt/nut until you can hear a ticking sound. Then tighten the bolt until the sound disappears. After that you tighten the bolt/nut 360 degrees and then you are finished.
This is a superior way of doing it according to them. I know nothing about this myself, but I thought I would post their recommendation. Maybe it is possible to use the same method on our Mopar engines?