The electric smog pumps? The two most common ones I see a lot of in the boneyards are 95-96 W-Body(Lumina,Cutlass) with the 3.4 DOHC. It is mounted under the right side wheelhouse. I like this one because it has a really neat universal mounting bracket. The other is the 94-96 LT1 B-Body(Caprice,Roadmaster). It is on the left side of the engine mounted low.