I want to say that they are the same thing...the pumps themselves are the same (they are a gerotor type, driven straight from the crankshaft). The biggest difference you will find is that an L67 S1 uses a different oil filter adapter so it can use external cooling lines, but that part *should* just bolt up to your current timing cover. The other option you can do is find what is called a cooler sandwich...an adapter that goes between the current oil filter housing and the oil filter. The sandwich supplies new in/out cooling ports for an external cooler.
Welcome, downwardly mobile yuppies, to the dawn of the Age of Nefarious.
1993 SSEi - FrankenJinx - dead and gone.
1994 SSE (136K strong) - 180* t-stat,HD alternator, most unequipped SSE on the club, XM radio, Kenwood CD/MP3.
2006 Chevy Malibu Maxx LTZ - Custom 2.25" manifold-back exhaust w/FM-80. Probably the only Maxx with this system.