DD15 LOSS OF POWER. INJECTORS or BAD DPF DELETE???

[Motorman Steve]

I recently did an in frame overhaul on a dd15, and now it is a complete wet blanket. Got brought in for a miss and a slight knock. Turns out it had a dropped intake valve. Customer decided to overhaul it because it had a bit of mileage on it. After the overhaul truck runs really smooth, but has no balls. Bobtail it drops 15mph going uphill and is only making 15psi boost. Truck was deleted before he came in and was having 0 issues with low power other than the chuck if valve missing. Other than the head and cylinder packs, i replaced the turbos with new units. At this point I'm at a loss. If this was a 12.7 i would have this sorted out by now but i am not as familiar with the new stuff. Any help / advice would be greatly appreciated. I've went over the timing twice, got fuel pressure, no leaks in the charge air cooler, I'm leaning towards this aftermarket head has some issues or maybe the injectors are shot.
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