[3] During a "remarkable if all too short" career,[3] Lockhart won numerous races on both dirt and board tracks, and the 1926 Indianapolis 500.

[6] Lockhart's big break came when he was signed as a relief driver for Pete Kreis's eight-cylinder supercharged Miller at the 1926 Indianapolis 500.

[5] Lockhart nearly stretched out a two-lap lead before rain ended the race on Lap 160,[6] becoming the fourth rookie to win the Indianapolis 500.

The intercooler added 8 mph (13 km/h) to his speed at his first race at Culver City in March with Lockhart finishing fourth after starting from the pole position.

On April 11, 1927,[7] Lockhart took one of his tiny 91 cubic inch (1491 cc) supercharged, intercooled[6] Millers out at the Muroc dry lake and set a land speed record of 160.01 mph (257.51 km/h) for a two-way average in the mile (1.6 km), with a peak speed of 171 mph (275 km/h).

[6] Backed by Stutz Motor Company, Lockhart combined two supercharged 91 ci (1.5 L) DOHC Miller motors, producing about 380 hp (280 kW),[6][8] the smallest-displacement car ever to make the attempt,[9] to set a new land speed record in the 122–183 cubic inch (2–3 litre) class at Daytona Beach.