It seems that in the 1970s the BMW 5 series was more reliable than the Mercedes W116 & R107 in Road & Track’s owner surveys. And as the burnout video shows, the BMW single row timing chain was stronger than the Mercedes chain in the 380SE/SL V8.
1977 BMW 530i burnout
Between 1970 and 1980 the Mercedes W113 Pagoda Roof SL and the BMW e12 530i were the 1st and 2nd most reliable cars Road & Track surveyed. They even gave fewer problems than any Japanese car!
Road & Track March 1979 BMW 530i (1975-78)
Problem areas 6 / Reliability areas 0 average for all cars 12/7
R&T Owner Survey BMW 530i
Road & Track August 1977 Mercedes 450SE/SEL/SL/SLC(1972-76)
Problem areas 9 / Reliability areas 0 average for all cars 12/7
R&T Owner Survey Mercedes 450 series