[William Dale Jr]

Originally Posted by chunterer

Ford wouldn't have ploughed money into a Mustang project (which was a car with only limited Ford marketing appeal in Europe being an American machine) when Sierra, a pukka European car was about to embark on an illustrious racing career.

I'd say you're right. On the Sierra Cosworth video by Duke, Stuart Turner said that the Sierra was chosen because it was really the only available European car; the Granada was too big, the Cortina was on the way out, and the Merkeur (and presumably the Mustang, too) were American cars and using them in Ford's European touring car efforts would have presented the wrong image.