[v8volvo]

Sounds like you have a good setup with plenty of flow, at least on paper. But clearly something is not working out correctly in the real world, either a defect in one of the parts, or some pieces of the system not playing well together, or there is a foreign object creating an obstacle somewhere.

With the 3" open exhaust I think you can rule out a restriction downstream of the turbo. How is the wastegate set up, how did you set spring tension, and what kind of wastegate control does it have? Is there an MBC inline in the boost signal line or did you set desired boost pressure just by adjusting the preload on the wastegate spring?

What kind of intake manifold do you have? D24 NA? If it's the stock D24T/D24TIC intake, did you shim or seal up or eliminate the over-pressure bypass valve somehow? If it is still there, any chance that it is getting pushed open and leaking back to the turbo inlet?

Have you reinstalled the pump and injectors back on the engine since getting them back from being checked over? If so was there any change from how it was before? A fuel system problem like a pump with sticking dynamic advance could still be part of the issue as far as EGT and smoke are concerned, although it wouldn't explain your intake charge pressure dropping below zero. Nevertheless, now that you know the pump and injectors are set to spec it would be valuable to see if that makes any difference. Though if they set them up for the specs on the new pump's body it might still be wrong for this engine. It might have been better to give them the numbers off the original Pinzgauer 10mm pump and ask them to try to match the fueling and advance curves of the new larger pump as close as possible to those.

It sounds like the symptoms you saw were intermittent, like it could sometimes build boost and make some power but other times it couldn't generate any pressure at all. Is that correct? Was there any pattern to the symptoms, like ambient weather temp, etc, that could predictably make the problems worse or better?