Has an MLB game ever ended 27-5?

Exactly once. On September 12, 1883, Cincinnati Red Stockings beat Allegheny Club (none) 27-5, and no MLB game before or since has ended that way. When it happened it was a scorigami, the first 27-5 in league history.

Where 27-5 sits among nearby MLB scores. Deeper blue means a score has happened more often; the outlined cell is the new one.

That makes 27-5 the 278th most common final score out of 330 that have ever occurred in MLB. One point away, 28-5 has happened 2 times and 27-6 has happened never.

Every 27-5 in MLB history

Date	Result	Season
1883-09-12	Cincinnati Red Stockings over Allegheny Club (none)	1883

Open the MLB grid at 27-5