Answer :
The allusion is when Ernie is compared to Muhammed Ali. Hope this helps!
The answer: The sentence in the passage that contains an allusion is: "But the boys swore that he was the Muhammad Ali of Nashville County." The allusion is to the American professional boxer, one of the greatest boxers of all time. An allulion is a reference to something else, it can be an indirect reference to a person, but it's up to the reader to make the connection.