Please, someone help i.d. these spindles

[a.c.1]

A buddy gave me these spindles to help upgrade drums to disc on my '68 c10shortwide. He said they came off an '86 1/2 ton. I started doing some measuring and not sure if or how this would work. The disc spindle measures at about and inch taller than my original drum spindle. The rotors that came off of them are 5 lug and 1 1/4" thick. The spindels themselves measure out similar 1 1/4" x 4 1/2 on the drum and 1 1/4" x 4 3/8"
Can anybody i.d these spindles or know if they will work on my '68. If so what will need to be done about the spring. I got the springs that came off this truck, they are the same height but are a little thicker.