Yes, good idea.
In general the Mercedes vans are interpreted according to their number designation XYZd. X=the capacity of the chassis in tons. YZ= horsepower rating of the engine, hundreds and tens position (07=70 horsepower)
Typical YZ numbers are 06, 07, 08, 09. 06=om615. Roughly the same engine as the 220d car (2.2l 4 cyl). 07=om616. Roughly the same engine as the 240d car (2.4l 4cyl) 09=0m617 Roughly the same as the 300d (3l 5 cyl). 08=OM352. A completely different engine than the 615-617 series. I think the OM352 is direct injection. Others were indirect injection. I say roughly because the van engines have a different injection pump and some other differences that increased the horsepower over the car versions of the engine.
The 309d bus for some reason, doesn't follow these rules.
The early van (pre 77) were made by Hanomag and were front wheel drive. I think they typically had the 615 engine.
These rules apply until the Sprinter series. I don't know the engines once the Sprinter came on the scene. Non of the pre-Sprinter vans were turbo'd by Mercedes. Some camper converters did put turbo's in their vans. There is a British company that specialized in aftermarket turbos on MB vans. I talked to a guy in France who had turbo'd his van and was happy with the results.
Tempo in India is still producing these vans. It also produces a turbo'd version of the 616 which it puts in it's equivalent of the G-Wagon.
Here's a good summary of the vans:
http://www2.mercedes-benz.co.uk/con...n_world/history/chronicle/1955-1994.0005.html