On an interesting note, I ran across three pieces of info in my travels.
The first is that Shelby (who had a hand in GT40's Design and tweaking) hated Ferrari. He blamed Ferrari racing for the deaths of close friends of his on the track, and was obsessed. The second piece is that Ford made a bid in the early 60's to buy Ferrari. Ferrari backed out, announcing that they were no longer for sale. Ford was left with no choice but to develop their own racing team, and that brought about the conception of the GT40 which ran very successfully until 1970 when a rule change made it obsolete.
Shelby wasn't the only one who hate Ferrari, read this quote:
"The following is a compilation of hearsay, legend, and gossip. Like all legends, it probably has at least a germ of truth. Unlike some, this legend does not make me want to investigate and determine where the fact lies. The legend is too much fun.
Ferruccio Lamborghini was a successful Italian industrialist. He owned factories making tractors and air conditioners, and had done quite well. Because of this, he also owned one of the great Italian success symbols -- a Ferrari.
That much is accepted as fact.
One day (the story has it) he was enjoying the fruits of his labor, tooling around the countryside in his Ferrari, when it began misbehaving, making noises he felt were not appropriate to Italy's finest sports car. Being in the neighborhood of Modena, and Ferrari's factory, he dropped in to get it serviced. Since Signore Lamborghini was something of a VIP, while the car was being serviced, he was shown into the Presence -- Il Commendatore himself, Enzo Ferrari.
Naturally, the conversation soon turned to cars, Ferraris in particular, and Signore Lamborghini helpfully offered some suggestions to improve the cars. Signore Ferrari was not appreciative -- rather, he suggested that Signore Lamborghini ought to confine his attentions to farm machinery, and leave the sports car business to Ferrari.
Lamborghini responded to this verbal slap-down as any hot-blooded Italian industrialist would -- he announced that he would build his own sports car, to show Ferrari how it ought to be done.
Ferrari's response was a classic of grand hauteur, and has been preserved for posterity: "Ecco," he replied, "une trattore gran turismo!" ["Well -- a sports tractor!"]
Doubtless Signore Ferrari later had many moments in which to think those words over. He had cast the gauntlet, and Lamborghini picked it up, determined to beat Ferrari at his own game. He gathered his best engineers, hired designers (in that part of Italy auto designers fall out of trees on you), and a year later, in 1964, unveiled the Lamborghini GT350 at the Paris Auto Show. It wasn't until 1967 that he achieved his goal, however. That was when he presented one of Marcello Gandini's designs, the Miura, to a stunned world -- the year he stole Ferrari's thunder."
Another site goes on to talk about how the Lambo bull is the final slap in the face of Ferrari. (Being a farm animal)
I wonder if these 2 stories find some common ground somewhere...