I don't see a COW listed...and all the rears listed appear to be posi...thought the ratios aren't exactly the same from the Chevy list.
http://www.2gta.com/1970ta.html
The famed 12-bolt GM rear axle was only available in the 1970 Trans Am and was available with four popular axle ratios. The base axle ratio for all engine/transmissions except the 4-speed Ram Air IV was a 3.55:1 Teamed with the RA III, an automatic transmission, and air conditioning, a 3.08 axle was optional. When equipped with a manual transmission RAIII and air conditioning, the buyer could order up a 3.31 axle ratio. Finally, the Ram Air IV's with manuals or any other non air cars could be built with a 3.73 axle.
COT
3-Auto
3.08
RA III w/Air Cond
COV
4-Manual
3.33
RA III w/Air Cond
COX
3-Auto
3.55
RA IV
COX
4-Manual
3.55
RA III
COZ
4-Manual
3.73
RA IV - Standard
COZ
4-Manual
3.73
RA III w/o Air Cond