1979 Chevrolet

It's supposed to get gas, ... And burn it. There's no way for any one cylinder to get more fuel than the others. What is more likely is oil running down from a cracked valve guide seal. That will lead to blue smoke from the exhaust and a fouled spark plug if it's bad enough. Too much gas will cause black smoke but it won't foul the plug unless raw fuel is pouring in from the carburetor but that would affect the four center cylinders the most, not just one.