https://tiptop25.com/fixing1984.html
"BYU '84 differs from those other teams in another way too: they did not play a single ranked opponent. The only so-called "national champion" that didn't (though Oklahoma came very close in 1956).
BYU's 1984 opponents went 61-85-3, placing their schedule 96th amongst 98 division 1A schools. And yet their performance was as weak as their schedule. They won five games by a touchdown or less, from a 20-14 win at 3-7-1 Pitt in their opener to a 24-17 win against 6-6 Michigan in the Holiday Bowl-- by far the worst bowl opponent ever faced by a so-called "national champion." How bad was Michigan? They finished 6th in the Big Ten, and the Big Ten was a horrid 12-15 against nonconference opponents and 1-5 in bowl games.
Let's start by comparing them to #2 Washington (11-1). Washington took a 16-7 upset loss at #10 Southern Cal (9-3), but since BYU did not play a team ranked so highly (or ranked at all), we can't fairly compare that result to any of BYU's. Washington's schedule was weak, and the only rated team they defeated was #6 Oklahoma (9-2-1) 28-17 in the Orange Bowl. Still, that is of course far more than BYU accomplished. And Washington's performance was very strong too. All but one of their 11 wins was by more than a touchdown (the only close game was 17-10 over 6-5 Oregon). That's 4 fewer close wins than BYU. This comparison is a blowout for Washington, and should not even be a debate at all. Washington even dominated BYU's bowl opponent, Michigan, in Ann Arbor. The final score was 20-11, but Michigan scored a touchdown and a 2-pointer in the closing seconds to make it look closer than it was. BYU, on the other hand, had to rally for 2 4th quarter touchdowns to beat Michigan on a neutral field, scoring the winner with under 2 minutes left."
Sorry for the text wall but I don't understand why UW doesn't claim '84. Blatant.