Allegro prototype
1962 Allegro prototype Ford

By 1962, Gene Bordinat and his team were working on the Allegro concept, which looked nothing like the production Mustang. However, it was significant since it established the basic proportions, namely a notchback coupe with a long hood, short rear deck, and compact cabin. Ford built 13 versions of the Allegro, most reflecting a European influence. This isn’t surprising given that the rising popularity of cars from the continent was one reason why Ford built the Mustang.