Welcome to the forum. The cheapest solution I know of to obtain 5 lug wheels all around is to install Chevelle rotors and Camaro calipers using a CPP kit, and then install a passenger car rear axle with a matching 4 ¾” bolt pattern.
http://www.classicperform.com/Instru...DF/6062DBK.pdf
Everything else I’m aware of either requires changing the front suspension to disc brakes, or installing custom drop spindles, all of which cost money. Although a popular swap, the later 5 lug truck rear axle is not a direct bolt in. It’s ¾” wider per side and will require relocating the perches to bolt up to your suspension.
I've never seen anything that will allow 5 lug drums to bolt on to 1962 spindles, and I don't think they can be redrilled to a 5 lug pattern due to the design of the hubs.