God dagen!
My suggestion is to buy a parts book off Ebay and even a parts interchange book if you have the funds. I'm in the final stages of a complete resto on a GMC 1946 1.5 ton. Part numbers for seals, bearings, brake parts etc are a huge help in locating these items. Once you have a GM number, the internet will provide many other numbers as these parts are commonly made by others. Keep in mind you GM only makes some of the parts on your truck, so they are all out there just under different numbers. Use the search feature in ebay that sends you an e-mail when some one posts your part number or word match. Check out:
http://chevy.oldcarmanualproject.com/http://www.stovebolt.com/techtips/identification/Advance%20Design/Har en god dag.
mjl
