To find the correct pattern, you'll need to:
1. Identify the exact model of your Chevy van: (e.g., G10, G20, G30, and even sub-models within those). This information is usually found on the vehicle's title or registration.
2. Check the wheel itself: The bolt pattern (e.g., 5x4.75", 6x5.5") might be cast directly into the wheel.
3. Consult a repair manual or online resources: Once you know the model, you can search for specifications online (like a parts website that requires you to input your VIN) or consult a repair manual specific to your year and model.
Without this specific information, it's impossible to give you the correct lug nut bolt pattern.