Dave, this is on the '73 280SEL 4.5. I've been out for the evening, just got home and will be looking at the shop manuals before hitting the rack. Looks like this might be a sealed alternator, but hard to tell as it sits pretty close to the valve cover/ head. Looks to have one three prong connector out by the edge of the case, another connector at the center and a single lead bolted 180 degrees out from the three prong.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.