Unlees you want to lower it, the aftermarket spindles are not needed. Find yourself a '73-'87 C10 and use the spindles from them. You'll have to change over the balljoints to the ones for the later truck (no big deal, they'll fit your existing control arms) and I beleive that you may have to use the outer tie rod ends as well. I'd suggest searching the site to be sure about that. While thare will be a slight increase in track width in the front, any competant alignment man should be able to get the caster/camber/toe correct.
For the rear, you can have axleshafts from the later diff shortened and re-grooved for the C-clip. You will need to change out the spider gears to the later 30 spline, as yours will be the old 17 spline. Might be better to swap the whole differential if you can get one reasonable.
