[rotorwrench]

The originals didn't have shims due to the large ball design of the thrust bearing. Some thrust bearings have smaller balls and are not as thick as the OEM types so shims are supplied to make up the difference. True, there is no load on the bottom knuckle and the shims can be placed there if you want. They are basically to adjust the fit of the upper knuckle stack with the bearing. They can be placed on the bottom of the thrust bearing between the bearing and the top spindle boss. They are generally some form of steel so they can take the load and they should not rotate since the bearing does all of the rotating. Eliminate all the play you can there without making the fit too tight. It can have a little clearance and still function as it should.

Some of these kits for the big 15/16 pins are crap. I've seen bronze thrust plates supplied instead of a bearing by the cheap crap manufacturers of these type kits. So far I've been lucky to find NOS FoMoCo parts but there aren't as many out there as there once was. Thankfully, they last a lot of miles so most folks that care for their antique cars will never wear them out.