This is an incredible record, I don't know how Jackson did it. Tyrone Keys is 2nd all-time with 26 sacks. Jackson nearly doubled that total - I'm not sure this record will ever be broken. Consider that Fletcher Cox, a 1st round draft choice (although not a DE), only had 5 sacks in 2011.
Billy Jackson played from 1980-1983. His most famous play is undoubtedly recovering the fumble that sealed the 1980 win over #1 Alabama.