You'll have to change the spindles, and possibly the control arms as well, if the 1/2 ton balljoints won't fit. Basically, a reverse version of what guys do to get front disks on the '63-'70 trucks. You might consider using the disk brake spidles, with the later balljoints for 1/2 ton, then use the 6 lug aftermarket rotors. That way, you get better braking and 6 lug.
