If you're working on the engine, you should:
* Consult a repair manual: A factory service manual or a reputable aftermarket repair manual specific to the 2002 Chevrolet Impala 3.4L V6 is absolutely essential. It will have diagrams showing the correct pushrod placement for each cylinder.
* Mark pushrods before removal: If you remove pushrods, carefully mark each one (e.g., with paint or a marker) to indicate its original location. This makes reinstallation much simpler.
* Use caution: Incorrect pushrod installation can lead to valve damage or other serious engine problems.
In short, there's no numbered sequence like "1, 2, 3..." for the pushrods. Their position is dictated by their physical location within the engine. Refer to your repair manual.