Hy Matthew Blair, and crenwelge, I found a Raybestos number for 15" X 5" rear brakes from 1956 - 65 H605 = Napa Up82487 $15.29, this is enough for one wheel, so you would have to order two sets for a single axle truck, unfortunately there are no dimensions in the description, but the picture does show four springs, two different lengths, hope that helps.
