With no local Ford product suitable following a change to international Group A touring car regulations at the end of 1984 as Ford Australia were not interested in homologating the XE Falcon for Group A racing, Johnson ventured to Germany and purchased a pair of Zakspeed constructed Ford Mustangs for the 1985 and 1986 seasons. While the Mustang years brought limited success, reliability and good-handling in the underpowered cars enabled Johnson to claim runner-up in the 1985 Australian Touring Car Championship, while his one and only victory aboard the Mustang was in the Group A support race at the 1985 Australian Grand Prix in Adelaide. The Mustang, like almost all other cars in the ATCC, was outclassed by the JPS Team BMW 635 CSi of Jim Richards who won seven of the championships ten races. The team had actually entered and qualified one of the Mustangs at Bathurst in 1984 (painted white with #71) in the new Group A category, but it was only there for a shakedown run and insurance should there a repeat of 1983 and was withdrawn after Johnson had put the XE Falcon onto fourth on the grid.