The Jaguar E-Type Semi-Lightweight, prepared from 1963 onward, is a racing version derived from the legendary production E-Type. Designed as a more affordable and robust alternative to the extremely rare Lightweight (only 12 examples built), it retains the original steel monocoque body but receives a bonnet, boot lid, doors, and hard top in aluminium, significantly reducing its weight compared to a standard Series 1. Only two official examples left the factory — a right-hand-drive roadster and a left-hand-drive fixed-head coupé — but numerous private conversions have since reproduced this specification, now highly prized in historic racing. Under the bonnet, the 3.8-litre XK straight-six engine is extensively reworked: wide-angle cylinder head, cast-iron or aluminium blocks depending on owner preference, and triple Weber carburettors, delivering power often exceeding 290 horsepower at 5,500 rpm. It also inherits D-Type wheels along with the suspension and braking upgrades of the racing versions. With its stripped-out cabin, roll cage, and silhouette still bearing Malcolm Sayer’s signature design, the Semi-Lightweight embodies an ideal compromise between the authenticity of the E-Type and the demands of competition.