From 1984 to 1990, Ford produced a special run of Mustang McLaren convertibles in conjunction with American Sunroof Company (ASC). These began in 1984, when an engineer created his own convertible Mustang after his wife was banned from parking her Mercedes SL in the official Ford parking lot. He showed his convertible to Ford, who agreed that it was a pretty spiffy vehicle.
At the same time, McLaren was working with Ford to create a special Ford Mustang McLaren with a new body style. It was a natural fit, to offer the special ASC convertible conversions on the Ford Mustang McLaren body. This was a very limited run of cars at first, but it proved popular enough that Ford continued the partnership through 1990.