Preservation of the past, a fine educational source and a chronicle of our changing times are three ingredients of a successful museum. Although restricted, the San Diego Automotive Museum in Balboa Park attempts to maintain these standards as visitors from the far reaches of the country spend some time there. It’s small by most museum standards, but curators manage to cram a lot of history into its 13,000 square feet. It’s being run by executive director Bob Swanson, who took it on three years ago as a fun project. One of six automotive museums in Southern California, the San Diego Automotive Museum, located at 2080 Pan American Plaza in Balboa Park, will celebrate its 20th anniversary with a $75 million Ferrari exhibition October through December. More than 30 classic Ferraris will be featured in partnership with the Ferrari Owners Club of America. Also, internationally famous race driver Dan Gurney will be inducted into its Hall of Fame on Nov. 22.   “We have expansion plans, but many of them are on a five-year program,” Swanson said. Swanson, who served four years on the board of directors, says running the museum is a matter of business management. “My real background is in property management,” he said. “I told myself someday when I retire, it would be fun to have a job like this.  “The museum world is different than the business world. It’s less competitive. Thanks to a couple grants we now have a curatorial room and another for automobilia. All the funding for the elevator is complete; now we’re awaiting permits and contractors.” Yet, he says, the auto museum is still not known in the community. For information, call (619) 231-2880 or visit www.sdautomuseum.org.