You didn't tell us the year and model car. Not a Chevy, so I'm going to guess a 1985 CA model 300D. Am I a genius, or do I own one? The "line" is a "tube". As mentioned, it is the high-pressure "liquid line" from the condenser to the filter/drier (black can in photo). Your AC is inoperable, but you hardly need AC in Oakland, unless you drive over here some summer day.

The correct air filter for your car is a round, squat can that sits on the "milk-stool" plate in the photo, with a rubber snorkel to the turbo inlet. They came only on 1985 CA models, but those are starting to hit the junkyards regularly. You can check inventory at PickNPull on-line. You will be OK for a year or so until you find one. The air filter element is hard to get and costs ~$45. For that reason, I grabbed a clean air filter from one at the junkyard a year ago for $1. So there was an 85, but I recall that was at Ecology in SF Springs. Methinks I can stack 2 common air filters to fit, for a cheap solution.