disc brake set up

Factory disc brakes for a 71 Scamp would be the Kelsey-Hays 4-piston calipers with 11-in. discs. All the parts should be available new from the parts store, eBay, or a specialty vendor like Inline Tubes — other than the spindles/hubs and the caliper hose bracket. Complete set-ups are for sale in the parts forum frequently. Sometimes used (you rebuild), but often fully restored and ready to go. The main issue is that you need to know what you need. Front spindles and hubs, ball joints, calipers and pads, rotors, hoses, hard brake lines, disc brake master cylinder. There should be lots of posts about this swap, with pictures.