Ignition timing rpm?

with a timing light, do you set the timing at normal idle speed or at a higher rpm? I have a 1984 chevy s10 2.8 v6, I found online that's it supposed to be set to 14 degrees, but I noticed that when I flashed the timing light on the mark, and reved it, the mark could not stay at 14, it moved, so do I time it at idle or what?

Set the idle, then set timing.1984, does it have a vacuum hose running from the carb/throttle body to the distributor? If it does then unplug the vacuum line at carb / throttle body with the rpm set, then input the line coming out of the carb/throttle body end and set timing. Reason being is everytime ya go to advance or retard the timing the rpm will change if ya do not. With the vacuum line plugged idle will stay the same when ya advance or retard the timing. there's also a way to set the timing at full advance if ya know the dist. housing #. It may be something like 24 deg. at 2400rpm and so on and so on

GM emp 31 yrs and avid backyard mech. with friends who are the same

On most EFI cars, and trucks, ignition timing is set at idle.

set at normal idle when you rev the engine the timeing automatically advances. generally refer to the correct service manual ps some timeing lights have an advance setting on them also be sure that you're at zero