Center section of manifold cracking..

[marek4792]

What would cause one to crack at the mounting flange, or on the outside of it? Pre doc EGTs and boost are in range for Volvo's small piping. Had RR demandate it using a proper 565 overlay verified by Rawze and had overseen the gutting process. We did briefly run a higher boost tune but the truck didn't like it drove coolant and oil temps into the red and since brought it back down. Engine has 665k miles and it is tired, and have an appointment in GA would like to get it figured out before hand. CAC is new and tested good. Tried Oem and {aftermarket) exhaust manifolds just to see. Using the correct turbo from the Chicago rebuildler I've mentioned on Haggais recommendation. At one point it didn't want to hold mounting gaskets pre and post demandate. Thoughts?