Very soft (too soft IMO) Babbitt overlay on the bearings for one. I’d be upgrading to some other type with higher load carrying bearings other than the standard replacement type which seems to be the norm. The cam is obviously being pushed downwards from spring pressure as the lobes open the valves. Crankshaft driving the timing chain and cam. And if you’re running a chain tensioner that adds to it. Someone can explain it better/ correctly/ accurately but I saw similar with my cam swap I did recently. And they are very soft Babbitt, more with the forward bearings, but still acceptable. I’m running a tensioner also. I’d look into higher load carrying bearings next time. A quick search will yield a few articles on the matter. Here’s just a sample:
Cam Bearing Selection and Installation
