The M15 was designed to compete in the 1970 Indianapolis 500, and although originally was going to be based on current F1 technology, it was ultimately decided to draw on components and learning from the extremely successful McLaren Can-Am cars of the day.
Power was from a Garrett turbocharged 4-cylinder Meyer-Drake which developed 750hp at 9,000 rpm.
Chris Amon and Denny Hulme were supposed to drive the two prototypes built, but Denny was injured in a freak accident when fuel was drawn out of the tank and ignited on the hot turbo housing. Chris Amon couldn't come to terms with the cars handling, hence the two cars were not entered.
The Third car (pictured here) was raced by Karl Williams in the 1970 Indy, where it finished 9th. It competed in one more race and was then retired.