Adding a turbo to a non-turbo detroit 2 cycle requires a few changes.
First off, the detroit 2 cycle doesnt actually have an "injection pump" the injectors themselves are the pump (called unitized pump. ) You'll need to get changed to higher volume ones. This should cost around $200 for a reman set of 6 injectors. I'll find out from a friend which part number you need if you wanna do this project. The gear powered fuel pump on the side of the motor is just basically to keep fuel flowing to the injectors.
Second, the throttle rise time buffer has to be adjusted to allow for turbo spool time before increasing fueling at the rack to keep it from smoking like a ******* whenever you hit the throttle. Also the governor may need to be slightly adjusted to keep the rack from hunting.
Finally, depending on your desire, you may want to intercool the turbo air prior to the blower, and aftercool the blower air prior to entering the air gallery. The 6-71T generally had neither charge air cooler on the stock configuration. It simply has the turbo feeding the blower directly.
All in all, its not a huge project, the turbo will be the most expensive part unless you can find a junkyard donor somewhere.
-Daniel