I saw the Bosche alternator covered in other posts, but I was just seeing it listed as 110 Amp. This guy on eBay is selling remaned 150 Amp Bosche alternators that he says bolt right on to the OM617. I just did a swap with this motor into my Jeep and the stock alternator will not charge my battery with my headlights and stereo on... Found this guy selling them on eBay for $159 so I bought one. Then I emailed him asking if it had a W terminal so I could try and get a tachometer working. He said it didn't, but said he would go ahead and add a W terminal at no charge. I will post back once I get it installed.

Not sure what happened to the link, here it is again. sellers user name is eagleautoelectric if the link isnt valid...

http://www.ebay.com/itm/360631744327