Oil PSI is fine (first thing I check). You could be right about the preload though as I believe my pushrods are about 1/16" too short. I have 273 rockers and most of the adjusters are maxed out all the way down.
If it were only a couple and not so messy...I'd say you could take a rag and while running...push onto the PR side of the rockers to make them quiet as verification.
BUT if you're using the stock style Jam screws you could update to a isky adjuster or crane...and get the length-a longer adjuster.
However you don't want to start throwing the geometry off at the end of The Rocker by having too much adjuster hanging down and fiddling with the acceleration of and lift.. so you might want to just get the right pushrod
