Has a FIBA World Cup game ever ended 86-78?
Exactly once. On August 13, 1990, Italy beat Angola 86-78, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 86-78 in league history.
That makes 86-78 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 87-78 has happened 2 times and 86-79 has happened 1 times.