The fastback Rapier was introduced in October 1967.
It was based on the Hillman Hunter using Rootes' 1725cc four cylinder engine with twin Stromberg 150CD carburettors and an alloy head. A choice of either a Borg-Warner automatic or a manual gearbox with Laycock de Normanville overdrive was available.
A Holbay-tuned version, the H120, was unveiled in October 1968. The H120 featured a redesigned cylinder head and twin Weber 40DCOE carburettors. The H120 is easily identifiable by its Rostyle wheels, go-faster stripes and bootlid spoiler.
For October 1969 a third variant, the Alpine, was introduced. The fastback Alpine was a de-tuned model intended to slot in under the Rapier in the Sunbeam range. It had a single Stromberg 150CD carburettor and less luxurious trim.
All Sunbeam fastbacks sold in North America were badged as Alpines - the Alpine Coupe being the North American equivalent to the Alpine, and the Alpine GT being equivalent to the Rapier.
In 1970 production was transferred from the Ryton plant in England to Linwood in Scotland.
The Alpine ceased production in 1975, the Rapier following in April 1976. A total of 46,204 fastback Sunbeams were built.