I was big into this years ago. I had an 83 300D with the 617. Not a big powerhouse but reliable. Not lots of mods available unless you spend the big money on the Myna diesel pump with the bigger elements.
I think the OM603 is a much better option. Much more power right from the factory and does respond well to minor fueling mods (it will roll coal) they are common to have cylinder head failure.
OM603 and 617 have similar wiring, really just a single 12V source to the fuel shutoff solenoid and glow plug controls. These are both mechanical injection pumps so not much science in getting one up and running.
There was a company selling adapters called 4x4labs back in the day selling adapter plate to chevy bellhousing. My plan was to use SM420/465 trans.
http://www.mercedesdiesel4x4.com/category_s/1833.htm
With all of that said, I would probably seek out a 4BT cummins, with the P7100 pump. The TH400 adapter is super common as is the manual trans adapter for the NV4500. It shares bells with the 6BT from 1st and 2nd gen dodge trucks. If you already have a 3550, it might be worth some research to see if you can use factory parts to make this work instead of custom ones.