The Sunset Service Center was actually across the street at 6407 Sunset. That lot was previously occupied by a Scrivener's Drive In; it is now a Jack In the Box.
Toast
A fuzzy shot of Scrivener's before it was replaced by the filling station.
Some businesses that have had the address of 6400 Sunset were S.G. Stephens Willy-Overland (1925); Hollywood Motors (1928); The Hollywood Unit of the Women's Voluntary Services (1943); a Muntz TV factory store (1952): First United Thrift & Loan (1956-61 more or less). None of these have led to pictures so far...