Ha! I went to Wikopedia, of all places, and found what I was after. Thanks. Seems like they ARE 2 totally different engines. The only thing in common is the displacement.
This is copied from Wikopedia;
7.3 Power Stroke
In mid 1994, the 7.3L Power Stroke diesel was introduced. Although the previous 7.3L had the same displacement, there weren't any other similarities between the two. The Power Stroke is an electronically controlled, direct injection engine with a 4.11 in (104.4 mm) bore and 4.18 in (106.2 mm) stroke creating a displacement of 444 cu in (7.3 L). It has a 17.5:1 compression ratio, and has a dry weight of approximately 920 lbs. This engine produced up to 250 hp (190 kW) and 525 lb·ft (712 N·m) of torque in automatic trucks during the last years of production, and 275 hp (205 kW) and 550 lb·ft (746 N·m) of torque in manual trucks. The 1994.5 to 1996/97 DI Power stroke had "single shot" HEUI (hydraulically actuated electronic unit injection) fuel injectors and ran a 15° high pressure oil pump (HPOP) to create the necessary oil pressure to fire the fuel injectors. 1994.5-1997 trucks used a cam driven fuel pump, whereas the 1999-2003 trucks used a frame rail mounted electric fuel pump. The California trucks in 1996 and 1997 had split shot fuel injectors whereas the rest of the trucks didn't get split shots until 1999. The difference between the split shot and single shot are the single shot only injects one charge of fuel per cycle, whereas the split shot releases a pre light load before the main charge to initiate combustion in a more damped manner. This controlled injection helps reduce the sharp combustion 'knock'. It utilizes a single turbocharger with a turbine housing size of 1.15 A/R. In 1999, an air to air intercooler was added to cool the charged air from the turbo making it more dense. The cooler, denser air would increase the horsepower potential of the engine, while also reducing exhaust gas temperatures (EGTs). Eventually, the turbine housing was changed to a .84 A/R housing and a wastegate was added. With larger injectors, the HPOP was advanced to 17° to change fueling characteristics. The 7.3 L DI Power Stroke was in production until the middle of model year 2003 when it was replaced by the 6.0L.
The www is just plain amazing.
