I've owned a couple. There are websites out there devoted to their history but I haven't looked at them for a long time. I got a shop manual for mine from a place in Rhode Island (?) which reproduces shop manuals. As you probably already know, 409 means a 4 ton van with 90 horsepower. 409's came in two different styles. One was the smaller van chassis and one was the larger van chassis (I can't remember the chassis numbers off the top of my head). I owned a 409d which was the smaller version. The '9' in the smaller version means it has the 617 5 cylinder diesel (non-turbo). None of the pre-Sprinter vans were turbo'd at the factory. They're all geared very low. My 409d was screaming at 65mph. They're also pretty gutless, especially at altitude without the turbo. I believe the larger chassis '9''s didn't have the 617 engine even though the larger chassis '7''s had the 616 engine. I may be wrong on this but I'm pretty sure the '9' in the large chassis had a truck engine and not a car engine. Although I haven't owned a larger chassis van, I've talked to owners and I believe their top speed is lower than the smaller chassis vans. There used to be a UK company which specialized in turbo'ing the larger chassis vans but I think you were still stuck with a very low top end. Robust, simple, reliable yes. Prone to rust--yes. Good for slow travel--yes. Good for fast travel--definitely not. There are a couple of places in the US with the parts data for the vans. The average Mercedes dealer does not have the info. The former exclusive G-Wagon importer in Santa Fe used to have the micro-fiche parts data and there's a guy in the pacific NW which has it. Parts can sometimes be hard to find in the US. I imported the parts I needed directly from the UK.
