Alex,
I hope all is well. I wanted to let you know I found a lead on a machinist that is making disc brake kits for these big old trucks. He's actually a member on the stovebolt forum and is Indianapolis (same as me).
He doesn't give out a parts list as its taken him many years to come up with this kit, but if you were to talk to him he will give you more details.
Swapping over to disc brakes may give you a better braking experience!
Randy Domeck
Indianapolis Fabrications
rdomeck@me.com
Indianapolis, In. 46254
317-258-0039