Delving Deeper is a mostly faithful clone of white box OD&D. S&W takes liberties, the most important few being the reduction of five saving throw categories to a single save number (that increments by +1 per level for, IIRC, all classes) and a total re-write of the treasure tables and allocation methods. One might say that Delving Deeper is the "OSE" of white box, and S&W is its "Labyrinth Lord."
(Editing to add: If I were to run a white box based game, I'd actually look to either "White Box Fantastic Medieval Adventure Game" or Chris Gonnerman's "Iron Falcon." Both are even clearer presentations of the original material, with the main difference being that Iron Falcon is a very faithful rendition of original D&D + Greyhawk, while WB:FMAG is a S&W-derivative clone that sticks to the first three booklets but does add a thief class that uses a beautifully simple single d6-based "thievery" progression for all thieving skills.)