Has an AFL game ever ended 78-66?
Yes. AFL has seen a final score of 78-66 6 times. It first happened on June 1, 1912, when Fitzroy beat Melbourne, and most recently on June 9, 2012, when Fremantle beat Richmond.
That makes 78-66 the 342nd most common final score out of 6,607 that have ever occurred in AFL. One point away, 79-66 has happened 3 times and 78-67 has happened 3 times. At one point the score disappeared for 73 years, between 1928 and 2001.