Yes you can, this has been covered a couple times here and many have done it... Use the search and you will see lots of info..
Also check this out:
http://www.sporttruck.com/techarticl...wd_conversion/
- As for swapping out with your 73' suspension if it is from a 2wd the front crossmember should fit i believe and try to grab some trailing arms for the rear end or a 4 link set-up..
WElcome to the board!