Drop Spindle disc brakes maintaining 6 lug?

[Calvin66c10]

hey everyone, i have a 1966 c10 swb that i am looking to buy a set of drop spindles for. My main intention is to maintain 6 lug 6x5.5" so that not only can I run stock wheels but i can run any obs 4x4 wheels or all nbs/nnbs 6 lug wheels. Only problem I have realized is the size of the front hubs fitting in a newer style rim. Do drop spindle kits reduce the diameter of the hub so I can run new style wheels or am i always gonna have to run wheel spacers to combat that?