Great question!
Not really sure, but during the work on the valve cover, I think, I just loosened them on #1.
Just to see if I could see, hear or feel something.
Bingo, I had the 180 psi number on the gage.
I had just a little interference on the #1 and #6 exhaust rockers.
So I just kept grinding and checking till everything cleared.
Just a small rub.
You can see in this picture the marking I placed on the high spot to check for rub.