The E-Type was initially designed and shown to the public as a grand tourer in two-seater coupé form (FHC or Fixed Head Coupé) and as convertible (OTS or Open Two Seater). The 2+2 version with a lengthened wheelbase was released several years later. The model was made in three distinct versions which are now generally referred to as "Series 1", "Series 2" and "Series 3". A transitional series between Series 1 and Series 2 is known unofficially as "Series 1½".
The Series 1 was introduced, initially for export only, in March 1961. The domestic market launch came four months later in July 1961. The cars at this time used the triple SU carburetted 3.8 litre straight 6 engine from the XK150S. The first 500 cars built had flat floors and external hood (bonnet) latches. These cars are rare and more valuable. After that, the floors were dished to provide more leg room and the twin hood latches moved to inside the car. The 3.8 litre engine was increased to 4.2 litres in October 1964.
Following the Series 1 there was a transitional series of cars built in 1967-68, unofficially called "Series 1½", which are externally similar to Series 1 cars. Due to American pressure the new features were open headlights, different switches, and some de-tuning (with a downgrade of twin Zenith-Stromberg carbs from the original triple SU carbs) for US models. Some Series 1½ cars also have twin cooling fans and adjustable seat backs. Series 2 features were gradually introduced into the Series 1, creating the unofficial Series 1½ cars, but always with the Series 1 body style.
The Series 2 introduced a number of design changes, largely due to U.S. design legislation. The most distinctive exterior feature is the absence of the glass headlight covers, which impacted several other imported cars, like the Citroen DS, as well. Unlike other cars, this retrograde step was applied worldwide for the E-Type, not just to Americans living under the authority of the NHTSA.
Other hallmarks of Series 2 cars are a wrap-around rear bumper, re-positioned and larger front indicators and tail lights below the bumpers, an enlarged "mouth" which aided cooling but detracted for the Series I design purity