Yes, the 360 is an AMC 360 (what else would it be?).
In 73 you have a dana 30 closed knuckle front end. Not terrible but nothing spectacular. Bigger turning radius than the open knuckle D44's that were offered in 74.
Your transmission is a GM TurboHydramatic400 (TH400). 3 speed. Good strong tranny, easy to rebuild, parts everywhere for em, just not very efficient (3 speed). it may or may not be a nailhead pattern. Get under the truck and check if it has an adapter (spacer) between the engine and bellhousing. 74 was the first full year of using a TH400 with an actual AMC bolt pattern, previous ones used a spacer ring and an adapter on the crank to move the flexplate back.
Your t-case would be a Dana20 if it's part time. Again, great case, plenty strong enough. Most people's complaint is that the low range isnt very "low" and that could use improvement. They are easy enough to twinstick if you so wish.
Rear end would be a D44, standard.
If you have a tow package you have 3.31 gears, if not, you probably have 2.somethings.
you have drums all around. have fun going bigger than 33s without discs or hydroboost. Its scary sometimes on my 33's with stock brakes.
The BJs spring kits are good. I'm running a 4" kit on mine and like it. Not sure about their SOA kits.
SOA requires a lot of work...shackle flip, hi-steer, brake lines, etc etc. A lot more work than people think.
I love my 73, but there are some weird things. 73 was almost a cusp year, lots of changes afterwards (d44 front, discs up front, changed to bridged rockers, blah blah blah).
if you want more info that is readily avaiable, and with way more people into FSJ's, join up on
www.ifsja.org.