Jaguar intended to build 18 'Special GT E-types' in 1963, but only got to 12 with the last one being ready in 1964. But the remaining six designated chassis numbers will get used now as Jaguar is set to build six perfect Lightweights to finish the job.
The Lightweights were homologated for GT competition by being designated a 'standard' roadster E-type fitted with a number of options. Those options varied from car to car, but the main modifications included all-aluminium monocoque and aluminium body panels, aluminium-block, wide-angle head, dry-sumped 3.8-litre XK engine with fuel injection, and aluminium hardtop. All chassis numbers carried an 'S' prefix.
This meant a weight reduction of about 250 pounds compared to the standard E-Type Coupe. Of the twelve Lightweights built, eleven are believed to survive today, but that's just about to change as Jaguar will hand-built in-house six more to the exact specifications.