EQUAL PARTNERS: Dianne Simon is an equal partner with her husband, former race driver Dick Simon, in their Dana Point race car business. . . . "He handles the engineers and the mechanics, and I deal with the accountants and lawyers," she says. They're in Indianapolis now, where they have four cars in today's race, including that of Lyn St. James, only the second woman to drive at Indy. "If she wins," Simon says, "it will mean a great driver won it, it will be great for us and great for women--in that order."