You don't need to see the timing ball to adjust valves, but it's good to have it well-visible for setting ignition timing. By watching the movement of the rocker arms, you can determine which cylinders' valves are ready to adjust. I use a method called "companion cylinder" valve adjustment, where I watch the rocker arm motion on one cylinder, and adjust the valve clearance on another one that's at the top of the stroke at the same time. I'll see if I can find one of the threads where I've detailed the procedure, and post a link to it.
Jerry

Edit: Check out this thread:
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=661274

I just noticed that thread covered adjusting hydraulic lifters. If you've got a solid-lifter engine, do the "rocking" thing the same way, but use a feeler gauge to set valve lash instead of the "zero clearance plus 3/4 turn" procedure. If you're doing a rough adjustment on a cold engine, set the valve clearance about .002" wider than specification, run it to normal operating temperature, and re-check the clearance after it's warmed up.
Jerry


Last edited by Hotrod Lincoln; 02/14/2011 4:20 PM.
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