I'm restoring a '64 Chevy 1/2 ton Stepside, and wanted to upgrade to front discs for safety, and maybe even add a power brake booster. After looking at several upgrade kits and their price (and wiping some tears away), I decided that would have to be a future project. Well, one of my lil bro's coworkers is restoring a '65 stepside. On a trip to see how his was coming along, I noticed he had upgraded to discs, and thought he had bought one of these expensive kits. Guess what? The spindles he had came from a '73-'87 Chevy 1/2 ton! Just change out your ball joints, and presto! Disc brakes up front, for about $70 from the local junkyard. Brand new rotors will run ya about $9 each.
On closer inspection of the truck, I noticed he had 5 lug rims on the rear also, and when I inquired about those, he told me the axles - not the entire rearend, which saves some more $$$ - were donated from a '72 1/2 ton rear end, with no adjustments. Voila! 5 lugs all around. Heck, the donor '73-87's brake lines were a perfect fit, and didn't even have to have any additional bends! The power brake booster even used the same two holes for the orig master cyl, but he had to drill two holes for the lower end of the bracket. The proportioning valve hung right below the booster, unmounted to the body, so no additional holes were drilled for it.
Hope I haven't wasted all these internet bytes on something that's already widely known. Just thought somebody else might like that info, and save a few bucks for something other than brakes.