[Captainfab]

With the '63 & '64 truck 12 bolt, converting to 5 lug axles becomes a little more expensive than for the '65-'70 truck 12 bolt. This is because the spider gears must also be changed to accommodate the new conversion axles. The '71-'72 truck 12 bolt will be a direct bolt in except for the panhard bar. The '73-'82 truck 12 bolt and '79-'87 truck 10 bolt can work but require cutting off the leaf spring perches and shock mounts and welding on trailing arm mounts while keeping the correct pinion angle. The '71-'87 truck 10 and 12 bolts are 1.5" wider than your current '63 truck 12 bolt.