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It's main two purposes are a liquid/vapor separator and rollover fuel tank leakage protection device. It allows the fuel tank to be "vented" to the carbon canister rather than straight to the atmosphere the way older fuel tank caps did, and stops fuel from draining out of the tank if you park your Vette upside down. Evaporating gasoline is quite a pollutant. Chevrolet intentionally made the connections between the fuel tank and separator, and separator and vapor canister line two different sizes to thwart what you suggested. Of course, someone who is determined can still make it work by looping a hose up and around.....
Both Corvette Central and Zip are now carrying this part. I don't know who manufactures the piece, and how good the quality is, but they have it for $50 and $60. That price makes it worth my while to replace it, and beats the crap out of the $100 to $125 that the used parts were going for (when you could find it).