I was kind of wondering if that was a miss print on that website, was just searching reviews for ratings and hadn't found any.
6 sp manual swap has already been done. This site list the CD at 0.36
Chevrolet Impala SS (1995)
The 4le60 has a .7 OD, T56 could bring that down to .5 with 3.08 stock gears. If I did the math right about 1160 rpm per mile.
Only 500 lbs heavier than a 2010 Impala that has a Cd of 0.33