Gonna jump in here. I don't know what rear end you have in your car at this point, obviously not an 8 3/4. Going to 8 3/4 you will have to rework or have a driveshaft made. Reading this post, if i am correct, you're looking at spending 3200$ on an 8 3/4 with disc brakes? I'm sorry but that's way way far out of line. I had a Strange S-60 custom built for my Demon with a tru-trac carrier for a lot less than that. Now mind you I am using drum brakes and running a big block. It looks like you're after a cruiser with a little pep? My advice is don't rush, keep an eye out for a rear end assy. There's one listed here for 750$ with 323 sure grip. How ever its pick up only. My point being there are deals that pop up, watch local adds in your area. I just think you can find better deals and use the money other places. Also being new to this car familiarize your self with the quirks of your car. Research the dimensions you need for the differential (length of housing, spring perch width) so if you do find one you're able to make sure it's what you want. You're wanting four wheel disc brakes? I personally would go with a factory set up on the front and look after market on the rear. For the front you will need upper control arms (lg ball joint 73 up vehicle) spindles (73 up) I believe your lower control arms will work with the later ball joints (not 100% sure on the 1968). My point being I hate to see someone toss money that can be used effectively other places. In my opinion for 6k you can do rear and brakes and have a sizable chunk left for else where. I'm not putting you down but research and ask questions. There are a whole bunch of good people on here that can and will guide you. Don't know your situation and if your doing the work your self. I'm sure there are members close to your area that may even be willing to lend you a hand. I guess my point is I have seen people in my life that start a project and get discouraged due to money going into it, and give up.