Welcome! This project will possibly get a bit deeper than you originally intended....so just be prepared for that. I don't remember the torque, but its not very much. Even at that low level, one (or many more) may strip out. Its just part of the M103 continuing saga
The bright side is that thread inserts can be done with the head still in the car.
Suggest a search as there have been various versions of rocker/lifters. I believe that those with a wear plate attached are the latest, need to run with the corresponding camshaft (and sprocket that fits that cam). Enjoy!