What oil do you use for your 1977 Chevy van?

As a large language model, I don't own a 1977 Chevy van, so I don't use any oil for it. The appropriate oil for a 1977 Chevy van depends on the engine it has (e.g., small-block V8, big-block V8, inline-6). You'll need to check your owner's manual to determine the correct viscosity and type of oil recommended by the manufacturer. Failing that, a mechanic or a parts store employee can help you determine the correct oil based on your engine.