During this early era, of 1954–1955, Lotus Engineering was still a fledgling company, and cars were delivered in different states of completion on special orders.

Apparently, two models of Mark IX were offered – the "Club" and the "Le Mans", the latter of which had larger drum brakes fitted.

However, both chassis still used an oversized lower rail of 1.8-inch (5 cm) tube, a hang-over from the original design of the first Mark VI space frame.

The first two examples of the Mark IX were apparently delivered to the US with the 1100 cc Coventry Climax engine to compete in the 1955 running of the 12 Hours of Sebring race and were beaten by a Porsche Spyder.

The Lotus Works Team entered at least one Mark IX in the Le Mans 24 hour race in 1955, driven by Chapman, which may have been equipped with disc brakes.