When launched in 1967, the Vixen was effectively a Grantura 1800S with a 1599cc engine from the Ford Cortina GT. Even though the 'Vixen' designation was introduced to signify the change of engine, to satisfy demand a few early cars were built with MGB power. The only external difference between the Grantura and Vixen S1 was a larger bonnet vent. In 1968 the Vixen S2 was introduced. Mechanically unchanged, the longer wheelbase (7ft 6in) chassis from the Tuscan V8 SE was used. The body was almost identical to the LWB Tuscan body, with longer doors, and Cortina Mk2 tail lamps replaced the round Mk1 lamps. The bonnet had a long bulge running from front to rear, which has subsequently become known as the 'sausage' bonnet. Required to clear emissions equipment for the US market but unpopular with British buyers, the 'sausage' was replaced by the Tuscan bonnet.

In 1970 came the Vixen S3 which was externally unchanged apart from the fitment of the alloy wheels from the Tuscan and revised air vents on the front wings. Mechanically the car now had the more powerful engine from the Ford Capri 1600GT. A small number of Vixen S4s were built in 1972-73, identical to the S3 except for the use of the chassis from the forthcoming M series cars, which replaced the Vixen.