CAT Men, Can you look up a 6NZ # for me?

I'm looking at a truck which has a 6NZ 27620 engine. It's a Ryder truck. The say they spent over 11K on a rebuild just around 100k miles ago. Can anyone give me any history on this engine, and most of all, tell me what it is capable of with it being the smaller HP C-15.

Would a Bully Dog be the best bet, or a reprogramed ECM. I'm not looking for huge power. 450-475 HP and 1650 ft lb torque would be fine with me. I am interested in long life and good fuel mileage. I'm afraid a Cat reprogram would kill the fuel mileage with a low nox file.

 

Thanks. From what I have found in Cat brochures for that engine, it will turn up to 450 HP with out any iron changes. No mention of torque. I am hoping for 1600-1650 torque. That would be good enough for me.