Southern California:
Ted Ernst Cyclery in Manhattan Beach was THE place. Ted was a six day racer and stayer back in the day and is incredibly knowledgeable about the classic stuff. Problem is that his shop has been going through all sorts of foolishness -- bought out by Triathlete Zombies, then back to Ted, and now I don't know what's going on. Look him up; if he's still doing his thing that's the place to go.
Another fantastic place is Bill Ron Bikes in Redondo Beach. He was a Campagnolo mechanic for the '84 Olympics so obviously knows his Super Record. He does have a supply of old Campy and other stuff, but he's got to be in a good mood to even consider selling it to you, and he'll charge you top dollar for it. He does do great work mechanically and will actually be happy to spin wrenches on your classic. And I've still got his phone number memorized: 310-540-2080. He's got a website too.
Last is a hidden secret: Discovery bicycles in Huntington Beach, or maybe it's just over into Westminster. On Warner Ave. just west of the 405, anyway. You'd never think it a good place for classics; from the street it looks like a typical LBS with an emphasis on cruisers and "comfort" bikes. And the staff is mostly teenagers who will stare at you blankly if you ask about toe straps or hi-lo hubs. So the best bet is to head directly to the service area where you'll discover the entire former mechanical staff of the old King's Colnago shop in San Pedro. The chief mechanic took his whole team from Kings and transplanted them to Discovery, and they know their stuff.
HTH!