The Lotus Mk 10 or Mark X, of which only 6 or 7 were made, was essentially identical to the Mk 8 but made use of the larger 2 liter Bristol engine. The Lotus Mk 8, Mk 9 and Mk 10 were transitional forms although they represent the first full bodied aerodynamic Lotus sports cars, they made use of the deDion tube as a rear suspension locator, and also inboard rear brakes.