The EX 181 was the last MG record car built at Abingdon and designed purely for straight-line speed. The supercharged MGA twin-cam is mid-mounted and drives a Riley RM-series gearbox to the differential. The chassis is tubular with MGA front and de Dion rear suspension, with quarterelliptic leaf springs. The body shape was arrived at by extensive wind-tunnel testing.

In 1957, with a 1500cc engine installed in EX181, Stirling Moss achieved a speed of 245.6 mph at Utah.

Two years later, with a 1506cc engine, American driver Phil Hill recorded 254.9 mph. This run by EX181 was the last successful MG speed record attempt and has not yet been beaten in terms of speed for the amount of power produced.