1954 manual,
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0406.htmlThe shims set the pinion depth, so the first install is a test to see if you need to raise or lower the pinion in relation to the ring gear. Depth is related to tooth pattern. If the pinion is not marked ( the late model ones are ), then install thin one and set up the whole assembly and check the tooth pattern. Be sure to tighten all the bolts and nuts, set back lash, and bearing preload. If the tooth pattern is off, then you need to remove or add shims to correct it.
The '54 manual should tell you which way to adjust the shims for the pattern you get. For that matter, about manual should have tooth patterns in it, and the newer ones probably have better pictures.
Joe
