I have a huge affinity for these cars.
They're quite a car. I came VERY close to buying quite a nice one in 2000, from a collector in Spokane, WA (I was majorly buzzed & flush on Intel stock options at the time, but decided to buy a historic house instead -- better investment, as I more than doubled my money on the house in less than 8 years). There were 2,677 Grand 600s made from 1963-1981, although they were not imported into the US after the 1972 model year because of tightened emissions and safety laws.
AMG massaged a few of them for rich clients back in the day (remember that AMG's first race car for the 1967-1968 time frame was the 300SEL 6.8, which used an M100 motor from the 6.3/600 that was bored out to 6.8L). Surprisingly, quite a number of Grand 600s actually still do survive -- I'd say probably 1,500 of them. I've personally seen probably 100 of them in person, and had the opportunity to drive one around the track at Portland International Raceway back in 2001, when I hosted the M-100 Club's 3-day annual gathering in Portland (for 6.3, 6.9 and Grand 600 owners).
There are several books out about the 600, two of the best books are by a German author named Michael Wiedmaier. Both 600 books he has done are only printed in limited editions of 2,677 copies, each individually numbered to correspond with a car. The first 600 book was published around 2000, and the second one (considerably more in-depth) was published about 2007. The first book costs around $200 (if you can still find it) and the newer one was well over $300 -- I picked up a copy at the MB Classic Center in Fellbach, Germany on my trip there last summer. These books are extremely difficult to find but document most all of the cars, particularly those owned by famous owners.
Hugh Hefner owned two of them. I sat in one back in about 2001 when I was visiting LA (the car had just been sold and the new owner wanted to show it off to me) and it had custom pink carpeting with a very long pile, and the inside of the glovebox also had this pink carpet in it. It was ... well ... interesting.
When I was at the Fellbach Classic Center in June there was a perfect 600 SWB parked outside, that I parked next to. I took some photos of it (I think I posted them in another post but they are also below). I think it was company-owned, given the license plate.
Attached are a few photos of the two Wiedmaier 600 books. They are very comprehensive and detail all aspects of the cars, including all options and variations, colors, etc.
The US authority on the Grand 600 is Karl Middelhauve of Wasau, WI (formerly of Woxall, PA). He and his wife Ruth are two of the kindest and most hospitable people you'll ever meet. Karl's amazing web site is at
http://www.mbgrand600.com He's done some amazing performance projects to 6.3s and 600s (which share an engine). Karl usually has about 8 or 10 of them for sale that he has personally restored. Here's a story where Karl talks about driving to the M-100 Meet I hosted in Portland (he mentions me briefly):
http://www.mbgrand600.com/Page500.html
Cheers,
Gerry