lowering a 71 swb step side

[adricar1]

I apologize if this has already bean answered but i am not sure on what to buy. as i am in the united kingdom these parts are not easy to come by
I have just bought a 71 swb c10 stepside, which this is not at present lowered

i have seen some pictures on here with a 5 inch drop on the rear and a spindle change and a 1 inch drop spring on the front.
What spindles do i need because the truck already has disc brakes on and that is mainly where i am getting confused.

do i need to get shorter shock absorbers, and i have also seen brackets to relocate them , is this necessary? and also a shorter sway bar? again any help would be most welcome.

a few pictures of lowered ones would also help me deciding what drop to go.