 Complete the following phrase:  Once again, ten drivers and cars traveled from the United States to represent USAC. A further two USAC cars were also in attendance, to be driven by Formula One drivers Juan Manuel Fangio and Maurice Trintigt, but set up and run by the American crews. Ferrari, as part of their requirement with the Automobile Club of Italia, brought two unique cars. The first was an older 375 F1 chassis using a modified V12 engine from 335 S sports car, and renamed the 412 MI. The second was a modified 246 featuring a Ferrari-built Dino V6 engine, enlarged to and equally renamed the 326 MI. Luigi Chinettis new North American Racing Team also entered a third Ferrari in the event, using an older V12 car which had originally attempted to qualify for the 