Hy 1960C60Viking according to my books your truck has a bendix brake system, I can find a number for the wagner crossover line but not for the bendix system. Try this fix instead weatherhead makes an adapter to go from 7/16" x 20 T.P.I. to female 1/4" inverted flare, that would allow you to make up your crossover line out of standard 1/4" brake line the part number is 7732 this fitting seals on its hex not on a seat so you might want to purchase the appropriate copper washer as added insurance for a good seal. Hope this does the trick for you.
