Stephen Cox blogs about Shelby American’s legendary Group 2 Mustang racers, Part 1 of 3. On a hot summer afternoon in late August 1966, the telephone on John McComb’s desk rang. On the other end was automotive design engineer Chuck Cantwell of Carroll Shelby’s legendary racing shop, calling with the surprising news that Shelby had a Mustang Group 2 racecar for sale. McComb was delighted since his prior inquiries at Shelby had been met only by rejection. He had raced MGB sports cars for years...