Biggest Upsets in College Football History: USC or Michigan?

There have been many upsets in the past and present in college football, which one ranks as No. 1? 

In 1942, Holy Cross, which was a 28-point underdog, beat Boston College 55-12.  It was the largest point difference Holy Cross has ever had as an underdog.

In 1972, Missouri, which was a 35-point underdog, beat Notre Dame 30-26.  That same year Notre Dame went on to the Orange bowl and met against the Nebraska Cornhuskers and lost 40-6.

In 2007, Appalachian State beat Michigan. A top-5 team losing to a Div I-AA school at home certainly ranks among the greatest upsets ever, but as was pointed out at the time, it wasn't the biggest upset in terms of the point spread.

USC losing to Stanford very well might be the biggest upset ever.  Stanford was a 38-point underdog when the line opened and in some spots grew to 41 points, making the Cardinal win, quite possibly, the biggest upset in college history.

There are many not mentioned, but these stand out to me as some of the greatest upsets ever.  What do you think?