In April 1975, the North American models got a slightly revised set of front bumpers which had rubber over-riders covering the full length of the bumper with embedded turn signals at each end, and the Zenith-Stromberg carburettors of the V12-powered cars were replaced by Bosch-Lucas electronic fuel injection. In 1978 the carburetors were similarly replaced with EFI in the 4.2 L 6-cylinder XJ6L. In May 1977, it was announced that the automatic transmission used behind the 12-cylinder engine would be changed to General Motors' three-speed Turbo-Hydramatic 400 transmission, in place of the British-built Borg-Warner used hitherto.
