Oooh finally a question I can help with...
Cams are wonderful things, they have what is called a base circle. They hit a point where if you turn in either direction the push rod or rocker doesn't move.
When you are adjusting the valves on an engine so long as the push rod or rocker isn't moving, your on the base circle. The lash is not changing during this period, it is as loose as it will get... exactly where you want it. When is top dead center? The intake valve was the last thing to close, this is top dead center on the
compression stroke.
The most marvelous thing ever invented for adjusting valves is the
remote starter, hit the button for a split second and bump bump bump. Intake valve is closed, now no movement... wiggle wiggle theres the slack.. its not changing. Set the lash and repeat.
(This is not specific to your engine, and the specs and whether its done hot or cold depend on your engine. This adjustment method works best on flat tappet, solid lifter engines... but it works to find TDC on the
compression stroke of any engine.)