I have been watching along and see the 60-62 front Torsion Swaybar modification is kind of a mystery. No one makes a specific one and if your like me, I like the torsion style suspension despite its down falls in handling.
I finished my 62 stepside frame off and so far logged about a 150 miles on it. Now that I have dialed in a few things like the brakes and engine/trans issues I decided to tackle the handling. I ordered from Summit Racing the "Addco 117" replacement 1-1/8" SB for the later C-10 and 20 trucks. I figure if it was not going to work they would take it back with out issue. Following are some photos of the installation that gives you an idea on how it went.
Mock up