Adding Rear disc Brakes, which way to go?

[Kenz72K5]

Ok, been a member for a couple of years, havent been very active as far as posting, but do read many. I started my build almost 3 years ago, this 72 Chevy K5 had been used as a Hunting Rig. but had a LS1 and a 6L80 that runs like a Scolded Dawg! I recently Retired from working on Jets after almost 38 yrs. from the DFW area, and Moved My K5, My 2017 ZR2 and Wife to The Big Island of Hawaii. so parts are hard to come by, It will be a Full Time Convertible. My Brakes are questionable at best, so im wanting to add Disc's to the rear. Im wondering if I would be better off finding a rear end from a later model GM truck with factory disc's, or getting a kit. im thinking of adding a Hydroboost system to it also. Any recommendations on which rearend would be
best, as a lot of Old trucks are still on the Islands! TIA !