Dozen of classic cars will make their way south through San Luis Obispo County today, the third and final day of the Mille Miglia North America Tribute. Patterned after the Italian Mille Miglia, or 1,000 miles, the rally began Wednesday in Santa Barbara, then made its way north through Paso Robles to Monterey for the night. Drivers went up to San Francisco on Thursday, and drove back to Monterey last evening. Today they head south on Highway 1 through Big Sur to Cambria, then on through San Luis Obispo to highways 101, 166 and 33 to Ojai, and back up 101 again to Santa Barbara. All the cars, including Alfa Romeos, Austin-Healeys and Ferraris, were built from 1927 to 1957.