the motors themselves are mostly the same between the 94-97 and the Superduty years. I believe the 94-97 have single-shot injectors, whereas the newer ones have split-shot, for a quieter effect. Turbos are wastegated on all years of the 7.3, but i believe the newer ones have a bigger turbo. Newer ones are intercooled, and probably have different programming. They are both direct injection using a hydraulic system. A downside the the newer motors in the super duties is the powdered metal rods that replaced the forged steel rods in i believe 2001. They are weaker, crappier, and prone to breaking if you put any serious power to them, but you'll be allright with your 94, as it will have the steel rods.