The Mirage project began in the spring of 1967 following Ford's decision to discontinue the GT40 programme. John Wyer, who ran J.W. Automotive Engineering, acquired a design study by engineer Len Bailey that aimed to improve upon the GT40's aerodynamics, weight distribution, and suspension. Working from a standard GT40 Mk I chassis, JWAE reshaped the greenhouse, squared off the front bulkhead, and dressed the car in sleeker bodywork incorporating carbon fibre alongside fibreglass — a technique that was pioneering for its time. The car was designated M1, and made its first run on 21 March 1967.
When the M1 appeared at Le Mans preliminary testing, it wore Gulf Oil's powder blue and marigold colours rather than Ford corporate livery, marking the debut of what would become one of endurance racing's most celebrated partnerships.
Three M1 chassis were built. The competitive highlight of the M1's short career was a victory in the rain-soaked 1967 Spa-Francorchamps 1000 km, driven by Jacky Ickx and Dick Thompson — the first outright win for Gulf Oil colours in international sports car racing. The M1 also won at Kyalami. At Le Mans the car showed pace but did not finish.
At the end of 1967, FIA regulations banned Group 6 cars over 5 litres that did not have 50 production examples, effectively excluding the M1 from the World Sports Car Championship. JWAE attempted to argue the Mirage was a reworked GT40 qualifying for Group 4, but the appeal failed, and the M1 was retired from WSC competition.
The M2, built in 1968 for the new 3-litre Group 6 Prototype class and powered by a BRM V12, saw little racing success. The open-top M3 of 1969, fitted with a Ford Cosworth DFV V8, also saw limited use as JWAE concentrated its resources on campaigning Ford GT40s during those two seasons.
After two seasons campaigning Porsche 917s in 1970 and 1971, JWAE returned to building its own car. The M6 — a new design using a steel-reinforced riveted aluminium chassis with a detuned 3-litre Cosworth DFV Formula 1 engine as a stressed member — debuted at the 1972 Sebring 12 Hours. A coupé variant, the M6 Coupé, used a Ford-Weslake V12 engine, but lap times at Le Mans ran sixteen seconds slower than the Cosworth version, ending that development path. The M6's sole international victory came at the 1973 Spa-Francorchamps 1000 km.
For 1974, the project was renamed GR7 to reflect Gulf Oil's continued sponsorship involvement. Running as "Gulf Ford," the GR7 placed second in the 1974 World Championship for Makes standings.
The GR8 represented the high point of the entire Mirage programme. At the 1975 24 Hours of Le Mans, Jacky Ickx and Derek Bell drove the GR8 to overall victory — Gulf Oil's last and, to date, final outright Le Mans win. A second GR8 finished third, crewed by Vern Schuppan and Jean-Pierre Jaussaud. The race was excluded from the World Championship for Makes due to fuel consumption regulations introduced in the aftermath of the oil crisis, but the result stood as a landmark achievement for the team.
Following Gulf Oil's withdrawal from international sports car racing at the end of 1975, American entrepreneur Harley Cluxton III purchased the entire Mirage operation from John Wyer and the Gulf Research Racing Company. Under Cluxton's ownership, with John Horsman continuing as team manager, the Mirage M8 finished second at Le Mans in both 1976 and 1977, first with a Cosworth DFV engine and then fitted with a Renault 2-litre turbocharged V6.
The M9 of 1978 introduced a new open long-tail body and turbocharged Renault engine; one of the two starters at Le Mans that year reached tenth place. The M10 of 1979, reverting to a 3-litre Cosworth DFV, failed to finish at Le Mans with either of the two entered cars.
The final Mirage was the M12, a Group C prototype with an aluminium honeycomb monocoque and a Cosworth DFL engine. Entered at the 1982 24 Hours of Le Mans with Mario Andretti and Michael Andretti sharing — their first race together as a father-and-son pairing — the car was disqualified twenty minutes before the start for a technical infringement involving an oil cooler placement. The programme was abandoned after Le Mans.
From 1974 to 1978, across every Le Mans appearance in that span, the various Mirage models finished no lower than tenth overall. The powder blue and marigold Gulf livery first worn by the M1 in 1967 became one of the most reproduced and recognisable designs in motorsport, enduring on contemporary racing cars and in scale-model collections worldwide. The 1975 GR8 victory stands as both the pinnacle of the John Wyer organisation's achievements and the definitive moment for Gulf Oil's racing legacy.