The 1966 United States Grand Prix offered the largest prize of the year, and Hill and Stewart lined up fifth and sixth on the grid. Hill suffered gearbox problems early on in the race but managed to carry on, while with other cars retiring Stewart found himself in third place by lap 35, a fair way behind Clark's Lotus in second. Hill finally retired with a broken differential on lap 53, and a lap later Stewart also had to retire when a cylinder liner broke. On the following lap the leader Brabham broke a camshaft, allowing Clark to nurse his car home for an incredible first (and it turned out, only) win for the BRM H16 engine.