To be sure, you'll need to:
1. Consult a repair manual: A Haynes or Chilton manual specific to your 1991 Dodge Dynasty with the 3.0L engine will show you a diagram and pinpoint the PCV valve's location. This is the most reliable method.
2. Visually inspect the valve cover: Look carefully at the valve cover; the PCV valve is usually near the top, often close to a hose that leads to the intake manifold. It might have a little hose going to the air cleaner housing or another part of the intake system.
Important Note: Without a repair manual, you risk misidentifying another part. Using a repair manual will prevent this and ensure you perform the maintenance correctly.