Not true, it's better to say these engines *can* put out 250HP. You will top out the injection pump around 180-190Hp. Any higher than that and you will be getting into changing the pump elements to get more fuel injected (Sending the heavy chunk of iron to finland, spending $2000. Not fun). The stock T3 is also only good to about 140hp and 15psi boost.

You best route for power is a Cummins 4BT. They start around 130hp and can get into the 250-400HP range for MUCH cheaper and less work than you can get these to do the same. Not only that, but the extra 0.9L and a longer piston stroke makes them a torque MONSTER.

If you still want an OM617, I'd look for a Federal 83-85. Late 82 had some minor factory changes like longer exhaust valve duration on the cam lobes. Avoid Kalifornia model engines from the late 84-85, the emissions stuff on the engines stresses the engine more and will just mean more work for you.