You need a scale that is accurate and measures down to 1 lbs. I found a trigger scale reasonably priced on amazon. Here is a link.
trigger scaleYou need to disconnect the drag link so there is no additional resistance.
Although the Service Manual makes this adjustment sound relatively easy, it is no easy task. The locking nut at the very bottom for taking the slack out of the worm gear is not easy to loosen. It is large, about 2-1/4” and is blocked by the oil filter. I did manage to get it loose after removing the front and loosening the back clamps on the oil filter which enabling me to slide it forwarded enough to access the locking nut. Using a large slip joint pliers (water pump pliers) I did manage to loosen the nut. After unsuccessfully making the first adjustment, it became apparent that I needed a special wrench for that nut or I will risk damaging it with the water pump pliers. The pliers kept slipping and was hard to loosen and tighten due to the ill fitment and limited room I had to work in and you’ll need a special wrench for the front adjustment nut. I fabricated a pin wrench that did the job. Here is the post that documented that fabrication.
https://www.stovebolt.com/ubbthread...-chevrolet-3100-project.html#Post1348862
