I can likely add to this once I'm at home. I was a press reporter for the race. I believe I have the official entry and/or the results. Jim Clark ran away and hid at this race!
It seems to me Pedro Rodriquez drove a Bimmer in the sedan, oops saloon, race but I'd have to see my results. I was at the race for three consecutive years and it all kind of runs together in the memory bank!
If I recall correctly, Chaparrals won the 12 Hours. Let me know what you might be looking for and I'll see if I can help.
Cheers.