[78w72]

Hydraulic lifters definitely can be sticky or get debris in them, there are products designed to free sticky lifters, MMO & seafoam can work but rislone makes or made a product specifically for this. Might be worth a try if you are seeing/hearing improvements to the ticking as mentioned in the last couple replies.

Ticking/tapping noise is a very common thing with most of the hyd roller lifters, especially the older ones like the original comps, I had a set of those that were noisy and the 1st suggestion I got from SD performance & comp was to add seafoam to the oil at the suggested amount or a little stronger for a sort time to see if it helped, not just 20 min idling, actually driving for 50-100 miles, it seemed to help a little but the lifters were defective or a few were loose tolerances and just noisy.

Does rotella have a 10/40 oil? Always thought it was 15/40 or more recently they have a 5/40 synthetic or 10/30. I would use a good 10/30 synthetic if you have a roller cam, or conventional if not, up to you on brand but with a mostly stock size broken in cam you dont need race oil like VR1 etc, or super thick oil, especially in canada or starting it at freezing temps.

Try a strong dose of MMO or regular dose of seafoam & drive it for awhile to see if the noise improves then go to more drastic measures if it doesnt.