The New Haven Register even quoted a source in 1940 that said that BC should not have been ranked in the Top 5 that year as they utilized semi stitched footballs in the first half vs. Tennessee in that Sugar Bowl win of theirs. So I'm not convinced that BC deserves even their #5th ranking for being undefeated, untied and knocking off #1 ranked Tennessee in the Sugar Bowl that year.
I love the internet.
https://en.wikipedia.org/wiki/1940_NCAA_football_rankings
OK, after the final week of football, the AP's top 10 were as followed: 1) Minnesota (8-0), who took over the top spot back in week 8 from Cornell, 2) Stanford 8-0, 3) Michigan 7-1, 4) Tennessee 10-0, 5) BC 10-0, 6) Texas A&M 8-1, who was the defending champions, 7) Nebraska 8-1, 8) Northwestern 6-2, 9) Miss St 8-0-1, and 2) Washington 7-2.
https://en.wikipedia.org/wiki/1940_college_football_season
There were 5 Bowls in 1940 and this was before several current arrangements (pre-BCS) were in place, such as the PAC & B1G Rose Bowl alliance. So, Rose Bowl - #2 Stanford beats #7 Nebraska, Sugar Bowl - #5 BC beats #4 Tennessee, Orange Bowl #9 Miss St beats #13 Georgetown, Cotton Bowl #6 Texas A&M beats #12 Fordham, and Sun Bowl unranked Case Western beats unranked Arizona St.
Minnesota went undefeated in B1G plan and beat 5 teams that were ranked at one point or another (Washington, Nebraska, Ohio St, Northwestern and Michigan); but, they did not win a bowl. So, I can see a bowl winning, undefeated team jumping them.
Stanford went undefeated in the PAC, was ranked #2 and won the Rose Bowl. During their season, they also beat 5 teams that were ranked at some point during the season (Washington St, USC, Washington, Oregon St & Nebraska).
BC went undefeated in eastern play and went into the Sugar Bowl as the #5 AP team and beat #4 Tennessee. During their season, they beat 2 teams that were ranked at some point in time (Georgetown & Tennessee).
Thus, looking objectively at the 'final' poll with a focus on the 3 undefeated teams at the end of the season, Minnesota did play a challenging schedule, went undefeated and did noting to warrant losing its #1 AP ranking. The same can be said of Stanford and, if Bowl wins are a big thing, I can see them leapfrogging Minnesota. BC also went undefeated and had a big win against Tennessee; but, they had the 'weakest' schedule that featured only 2 ranked teams with two major out-of-region games against a pair of mediocre SEC teams in 1940 in Tulane (5-5) and Auburn (6-4-1). So, yes, BC had a very good season in 1940/41 and did well to go undefeated. But, their schedule strength and overall accomplishments puts them behind the other 2 undefeated teams of that year - Minnesota and Stanford. Thus, the evidence supports the NCAA's official records that BC DID NOT WIN a national championship in football in 1940/41. The only saving grace is that the 1 guy who voted Tennessee as the national champion was even more delusional and likely still works at ESPN.