3.31:1 gears in 8 3/4 open end????

8 3/4 gear ratios thru the years. 1957-1972.

2:76, 2:93, 3:23, 3:31, 3:55, 3:73, 3:91, 4:10, 4:56, 4:89, 5:17, and 5:57.