Engine brake troubles need some input

[Nater1977]

I have a 2008 CM871 fresh rebuild (in-frame). Tuned correctly, With a new head as well, This is a w900. I use it mostly for towing with a DTU on it. And I also use it for low boy work as well. On these extremely hot days my coolant temps are running 180 to 205 oil temp is around 210-225 not loaded but when pulling hills. When loaded with total weight between 60,000-120,000 coolant around 195-210 fan comes on then stays around 200-205. The oil temp will run around 230-245, pulling hills. OIL PRESSURE IS ALWAYS AROUND 35-40+ I do notice my engine brake on the 3rd stage, When boost gets closer to 30 Psi it sounds and feels like I am loosing compression and the truck starts to have the misfire feel. (Skipping) Shaking the cab like a bad U-Joint, was getting worse at hotter oil temps. I have been chasing this down. Reading all posts I could find, I am thinking I am loosing head pressure. I have replaced all bushings on rocker arms, checked diameter of shafts, all in spec and detents are looking perfect. Checked engine brake rocker arms looks to be in spec but weary of the pistons in the rocker arms. Retest, getting oil up to 210 and still having the same issue. As of 06/27/2025 I Replaced all the engine brake rocker arms, The performance is 90% better but around 1500–1400 rpm and lower I can still feel and hear a very slight miss/loosing compression. As a technician, it's not right. I believe the oil temps are within spec from research, but I feel would they should be lower.
Any help would be great, I would appreciate it, thanks!