Does not sound good?
It depends on the guy that designed the reconfiguration. Detroits are extremely modular engines. Parts from an 8V53 would fit on that engine, and vice-versa, sorta like Lincon Logs....stuff will fit in all types of configurations. So, "if" they knew what they were doing it could be a nice set up, make good hp and last 10,000 BMOH's.
There should be a specific book for the reconfiguration, detailing everything about the engine from liner P/N, injector size, turbo ASR & P/N, etc....is there a book, or build sheet??
It is difficult to find the right people for such experiments. Most certified DD mechanics know what can be done, but they won't share the info...they stick to the book for CYA reasons, can't blame them.
Typically Detroit HP levels and longevity are measured "by the hole". A 71 series can make 85-90hp per/hole...but won't live long. For a 71 series the Sport Boat balance comes in around 70 HP per/hole....for a 2,000-3,000 hour engine. The 53 series will be less, maybe 50 HP per/hole (assuming aftercooler, etc)...the 92 series will be more, say maybe 85 per/hole @ 2,500 hours.
Now reduce those numbers to 30-40 per/hole and you have a 10,000-20,000 hour engine. Take your pick (the numbers may shift around a bit but that holds true for all diesels)