it's not a terribly difficult swap, just lots of heavy knuckle busting back breaking work.
on the rear, PF hit it right: you'll need the shock plates & u-bolts, shorten the drive shaft and it's otherwise a bolt in affair. you may or may not need the e-brake cables, but grab them just to be sure. plan on a new brake drop line from the frame to the axle as well.
up front is a little more involved. you'll keeps the stock 66 K and lower control arms (unless the 73 lowers are in better condition), but if they have sway bar tabs you don't want them (more on this later). so basically you'll be taking the upper control arm, spindle, and then all the brake related bits: caliper, caliper bracket, splash shield, rotor, master cylinder, distribution block and safety/porportioning valve block. and the V8 torsion bars to replace the floppy /6 ones you have.
tools wise, you'll need the basic wrenches and sockets. notably, you'll need a 15/16 for the lower control arm nuts and lower ball joint attaching bolts. both socket and wrench. specialty wise you need a ball joint separator or *whispering* a pickle fork and a tie rod separator. and a BFH, you'll mos def need that. if you're rebuilding the suspension you'll need a ball joint socket and to fashion a tool to r&r the upper control arm bushings (piece of pipe, some washers, bolt, nuts). the lower control arm is a little trickier. if you're doing stock rubber lowers have a machine shop press them in, if you go poly you can DIY.
on brakes: if your car is manual and the donor is manual, swap everything over including the pedal pushrod (with a new keeper!!). if your car is manual and the donor is power and you want power, swap everything over including the pushrod-- you *might* have to open up the hole in the pedal or the pushrod slightly. if your car is manual and the donor is power, just take the master and use your push rod, if your car is power and the donor is power, you'll need to find the correct pushord or buy an adjustable one. or skirt all of that and buy an adjustable one from the jump to cover all your bases.
on swaybar: because the donor is 73+ none of the swaybar stuff is applicable to your needs. on the 73~76 the swaybar tabs are basically in the center of the arm, which could present a challenge later on down the line if you decide to fit a bar down the line. so if the LCA's have tabs, you don't want them, if they don't have tabs and they're in better condition than yours use them.
on steering: keep all your steering stuff the same. with the exception of the centerlink-- you'll need the 64~66 V8 specific one if you swap to a V8. otherwise, you're just going to pop off the tierods and leave everything else alone. i mean, besides rebuilding it.
pro tip: bust loose the upper and lower ball joints with the arms still on the car. otherwise you'll need a heavy bench with a big vice to handle them or you'll be chasing the assembly all over the garge floor and that ain't fun for nobody.
ETA: i forgot brake lines. you'll need to do some minor rerouting and/or tweaking, adding there. so either buy a kit from an online supplier or roll your own. nothing crazy though, just some bends and flares.
