jrsavoie
Recruit
Most suspension/steering parts have torque specs included with them in the box. I go with those instead of "the book" simply because "the book" is based off of factory OEM parts and what the factory torques to. Replacement parts (high quality brand name, not generic bargain cheapies) may use a better metalurgy or have a different thread count (fine vs. coarse) than OEM and thus require different torque specs than OEM. If you sources have different specs for the same part (ie: outer tie rod ends) that are close together like 35 and 40, I use the higher number. If there is a wide disparity like with your stabilizer links with 35 and 13 (what?) it could be due to a change in construction/materials. If the difference in specs is like between 75 and 90, I split the difference, then tighten until the first split in the castle nut aligns with the hole in the stud. (Note, I HAVE recently ran across replacement parts (daughter's Dakota) that don't use castle nuts but nylocs instead. Those I torqued to the spec provided (which wasn't OEM) no question asked.
The AC Delco Professional Upper ball joint 45D0064 does not have a torque spec on the paper. It just says install to the proper torque specification