help with bag and bodydrop on my 68

[kaotics]

so i have a 68 gmc ive been collecting parts for awhile now,
its basically just a 250/3spd truck but gonna go pick up a 292/4spd in a month to put it in,
now i wanna keep my drum brakes as i just redid everything, ill go to disc when i build a new frame over winter for hydraulics

now from reading i cant use drop spindles on a drum brake setup, so cupping the lca's lay frame with a 3-4inch z?
then im gonna door it or cut it down to where both front rear bumper sit flat on the ground, with a re7 will i be able to untuck a 22?
any help would be great, right now im just tearing the truck apart and probably pull the box tomorrow maybe start mocking up the bags sunday