im not exactly sure if the same values apply to the v6 pulleys but on mbworld in the s/c v8 engines the torque values are ranging from 200 ft/lbs to 275 ft/lbs plus 90*. this is a huge amount of torque that ensures the bolt will not come loose .
maybe jake can chime in as to the proper torque need for the 181,185 pulleys they sell or rob for the 178