Re: LOTS of questions about CJ-5
First off, welcome.
Second...sounds like you're starting off with a pretty good setup.
Next, please add a little more info to your profile....or you will suffer the rath of Leve.....update....never mind...Leve's fingers are faster than mine
And what we really need to know to answer your questions is what type of off-roading you want to do. Considering some of the mods you want to make to the engine, it sounds like you want a road beast and not a rock crawler.
Driveshaft....CJ5's have short wheel base. I personally don't like droping the xfer case...it's only a bandaid. Do it right and go with a CV driveshaft. You point the pumpkin right at the tail of the xfer case and the CV joint does the rest.
Loose the extended shackles....Skyjacker springs are some of the stiffest around....if you have the money, loose them as well. There are better ways to lift your jeep.
Is the 3 speed tranny an auto or manual?
Now the engine....for the most part, a 72 had little or no smog devices. Truth is, all the stuff you want to put on it will hurt your rock crawling rather than help. Headers are high maintenance and only help the upper 20% of your RPM range. Most off roading uses RPM ranges of 2500 and below. In addition, carborators are prone to flooding on trails, especially when you are parked on the side of a mountain. Personally, I would sell the engine and tranny and find a good low mileage fuel injected engine...say a Chevy Gen III TPI...you will get better gas mileage, lots more power, much more driveable, and it won't stall on hills.
BTW...use the search function.....there is a ton of info already posted...you just have to look for it...I get better results when I put the key words in quotes ""....for example, "SOA".
Fill our your profile...figure out how you want to use the jeep...do some searching and then come and talk to us...