Where is PCV valve on Chevy 4.3 v8?

There is no Chevy 4.3 V8 engine. The Chevy 4.3L engine is a V6. The location of the PCV valve on a Chevy 4.3L V6 varies slightly depending on the year and specific engine configuration, but it's generally found on the passenger side valve cover. It's usually a small, plastic or metal valve with a hose connected to it. You'll need to consult a repair manual specific to your year and model for the precise location. A quick online search for "[your year] Chevy 4.3L PCV valve location" should yield diagrams and photos.