There were recently two lengthy discussions about shoulder belt installs in earlier trucks than yours, but the same info applies. Here's one of the threads.
In addition to Julianos, you can look on ebay, pull a set from the junk yard, or get them from NAPA. Keep in mind the length and attachment of all belts is not the same. Some retractors bolt to the body, others to the floor. Some of the shoulder attachmemts incorporate 'extensions' and others don't. etc...
http://www.stovebolt.com/bboard/cgi-bin//ultimatebb.cgi?ubb=get_topic;f=20;t=000471
'51 Chevy 1/2 ton w/'62 261, HEI, offy, fentons, dual carter/webbers, t-5 & 12 bolt posi
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