Also 1980, 56-6. So get your facts straight, it was the largest margin of victory in 28 years, not 70. Is that what yewts have been saying over on their board?
And at least that game was still close at half-time. There have been many years where BYU had already blown out yewtah by halftime, and played the scrubs most of the second half, which made the scoreboard look much closer than the actual game. The 70-31 game in 1989 comes to mind, among many others....