Has a Copa America game ever ended 8-0?
It has. 8-0 has been a Copa America final 2 times in 1,738 games. The first was Argentina beat Paraguay on October 20, 1926; the latest was Argentina beat Paraguay on October 20, 1926.
That makes 8-0 the 26th most common final score out of 36 that have ever occurred in Copa America. One point away, 9-0 has happened 4 times and 8-1 has happened 2 times.