rear disk brakes on a 72 4x4

[blazin]

is there a kit to do the conversion for my 6 lug, 12 bolt 4x4? ive looked and cant find. someone must have done this, ive seen it done. is it worth it on a 4x4? also i wantt to replace my booster setup. my engine is a high hp 383 and with a canister, my brakes are crap. so should i go hydro boost or vac pump? to replace the booster setup its about 400 bucks and most likey 1000 to do hydro. is it really worth it. i am running 35 inch tires.

any help would be great.

sterling