Yea I went to your thread and looked it up. It’s a hydraulic and a nice easy lobe so I’m gonna say a lifter isn’t pumping up. Right after shutting it off you shouldn’t be able to push down on the pushrod side of the rocker at all. It should feel solid. If any are spongy there’s the noisy one.
I pulled the rockers off after it got up to temperature and pushed down on each push rod by hand. Not sure how hard you’re supposed to push on them, but I pushed as hard as I comfortably could and they all felt solid
