Jaguar XJ Numbering

Just prior to World War II Jaguar, known then as SS Cars, started using a numbering system beginning with the letter X for internal projects. X meaning experimental, XB for military chassis projects and XF to XK for engines. This numbering system has never been consistent and there appears to be many omissions and duplications.Number ProjectXJ3 3.4-litre and 3.8-litre S-Type saloon cars (known