Newbie : 69'C10 LWB to Buick 455/Th400

[Sebambam]

Hi guys
i am a new 69' C10 LWB owner, its a pretty rough truck but i dont mind to much since i am looking to build a "budget" Street Machine/Shop truck kinda lol.
I am not to worried about the body i will keep it most likely "patina" BUT it will get a BUICK 455/TH400 combo.

I want to start with the Brakes and convert the POWER Drum brakes to FRONT DISCs.
My truck is a 6 lug and i was wondering what other reason but wheel selection would i have to convert to 5 Lug?

Any Parts list for a front 6 lug Disc conversion Kit? I am looking into a 2.5 drop spindles

later i will go with a
+3/5 drop Kit + C notch

further the truck is a Standard transmission and i will convert to AUTO (TH400)
should i go with a floor shifter or should i look for a column?

Further regarding the BUICK 455 swap ( i know the Buicks pretty good),
my truck has the old sbc 350 in it so i have the right frame brackets, what mounts would i want to use? has anybody done that swap and can give me some insight?

Any kind of input is welcome..
as i said im a C10 newbie