Has a FIBA World Cup game ever ended 86-83?
Exactly once. On September 2, 2002, Brazil beat Angola 86-83, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 86-83 in league history.
That makes 86-83 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 87-83 has happened 1 times and 86-84 has happened 4 times.