The engine, a 3,442 cc inline 6-cylinder with an aluminium cylinder head and twin SU carburetors, produces 160 hp at 5,500 rpm at the standard compression ratio. It was an advanced design for the time and replaced the SS100's OHV with a DOHC engine.

The model name was determined by its top speed in excess of 120 mph (193 km/h), and established Jaguar's international reputation as a performance car manufacturer.

This particular example is equipped with wire wheels, which were an option, because of this the distinct rear fender spats are not installed as they would interfere with the center lock nuts.