Equipped as standard with the Cosworth Mk.IV engine and with either a Renault Dauphine gearbox or Hewland-modified VW box.

Compared with the Lotus 18, the 20 has a much reduced frontal area and lower centre of gravity, aided by the fact the driving position was reclined so the driver was nearly lying down, compared with being more upright in the Lotus 18.

A 1962 Lotus 20 can be found hanging from the ceiling on the first floor at the Canadian Automotive Museum.

The 20B was mostly the same as the 20, but with sway bar and stock inboard drum brakes in the rear.

[1] A Lotus 20 was entered in the 1965 South African Grand Prix for Dave Charlton but failed to pre-qualify.