Should be a Detroit. Had a turbo version on a 95 C2500. Good motor, just a little lacking on power. There is a bleed screw close to the upper thermostat housing-- crack it open, and crank till you get fuel, no bubbles. you don't have to bleed the injectors.
As for the Duramax being the laughing stock of diesels-- you have to be kidding. Go find a powersmoke that gets the same mileage and horsepower without using all aftermarket chips and such. As for the Cummins, great motor, nice milage, but really heavy and needs chips to make any decent power.