3/4 to 1/2 ton switch

[longhorn69]

so i have a 69 longhorn. i have already swapped my front end over to half ton hubs with the conversion spindles, and now it's time to swap the rear end out. just wondering what i should be looking for when i pick up a 1/2 ton rear end. i know it should be pre 86? and 2wd. can i just grab any rear end and it will fit? also, should i swap the 1/2 leaf springs in for the 3/4 ton ones? i dropped the front 3 1/2 in, so the back will need to be dropped 5 in or so, and i will be wanting to put a disc brake kit on the back. any help i can get is appreciated, i want to get this truck rolling!