The race was won by British driver Jackie Stewart driving a BRM P261. He took a forty-second victory over the Ferrari 246 of Italian driver Lorenzo Bandini. It was Stewart's second Grand Prix victory after winning the Italian Grand Prix the previous year. Stewart's team-mate, fellow Briton Graham Hill finished a lap down in third position in his BRM P261. The only other driver to be classified as a finisher was American driver Bob Bondurant driving a BRM P261 entered privately by Team Chamaco Collect.
Race report
The first World Championship race of the new 3-litre engine formula was held in Monaco. No team was ready for the new regulations, not even those who built their own engines, like Ferrari and BRM, with several teams starting the race with 1965 engines still in place, some of them enlarged Coventry Climax V8. Even pre-1961 engines of the 2.5 litre era were used again, namely the 4cyl Coventry Climax. Some had downsized sports car racing engines to suit, but these were heavy and lacked power. As a 4.2 litre DOHC Ford Indy V8 engine had helped Jim Clark and Team Lotus win the 1965 Indianapolis 500, Bruce McLaren had contracted third parties to make the smaller 3.0 L (180 cu in) Ford 406 that had been chosen by Team McLaren for the F1 constructor debut with the McLaren M2B. It lasted for only 9 laps in the race before leaking oil.
Another new engine based on an American Oldsmobile V8 was the Australian Repco-Brabham V8 in the back of Brabham's new 1966 BT19 chassis. John Surtees, though still recovering from a crash at Mosport Park, led for 14 laps from Jackie Stewart, Jochen Rindt and Denny Hulme until his differential broke, handing the lead to Stewart. Hulme retired whilst Graham Hill and Jim Clark disputed third place before Clark's suspension gave out. Meanwhile, Lorenzo Bandini was smashing the lap record before having to ease off to prevent the front brakes wearing out. Stewart won from Bandini with Graham Hill third and Bob Bondurant fourth the only other car past the line in a race of extreme attrition. New rules meant that cars had to complete 90% of the race distance to be classified and eligible for points, meaning that whilst Guy Ligier and Jo Bonnier were still racing, they were considered far enough behind to have actually retired. To this day, this race holds the record for having the fewest classified finishers in a single race in Formula One history.
