Vic Hubbard Speed and Marine. Yup.I don't know of too many left around here.
I consider Napa and CarQuest to be a little bit different than AutoZone or O'Reilly. At least around here they're independently owned and operate a lot like an independent. They might have access to a big catalog of affiliated parts, but not necessarily everything.
There was one I liked using called Vic Hubbard. They had several locations but eventually were down to one. That's where I got Redline SI-1 fairly cheap years ago. There was one store in Fremont, CA I found by accident that had almost everything ACDelco. Don't remember the name. But over the years I bought ACDelco cooling tabs and even an ACDelco 51R battery.