In a 10-game schedule, which was the norm for ND through 1968, the closest analog to an 8-5 finish (.615) is 6-4 (.600), followed by 6-3-1 (.650). In an 11-game schedule, the closest analog to 8-5 is 7-4 (.636), followed closely by 6-4-1 (.591). In a 12-game schedule, it's 7-4-1 (.625), followed by 7-5 (.583) with 8-4 further away (.667).
ND fired Brennan after a 6-4 season in 1958, which notably was capped by a win at Southern Cal. The knives were out for Devine after his 7-4 season in 1979. Faust remained on thin ice after his 7-5 seasons of 1983 and 1984.
This is the context for the forthcoming press release that Kelly is the first ND coach ever to win 8 games in his first 5 years. He's still below .700 (45-20, .692). But he's more likely to get an extension than he is to be fired.