5.3 swap questions

[1984 t type]

Hi all, im new to the site and was looking for a lil info on a project that i want to start.
first off i ran across a great deal on a 5.3 out of a 2008 chevy tahoe with 2500 miles that was wrecked (was a flex fuel truck) basically im trading some spare grand national parts for it so there no cash out of pocket on my end, but heres the catch the guy who pulled the motor was planing on putting it in a car so he didnt get the trans out with it also he didnt get the ecu, pedal, or harness, all thats there is the motor. My plans was to put this into a mid 80's 4x4 suburban so my question is with all the parts thats missing is this going to turn into a high dollar nightmare of a project or are the parts easy to come by and reasonably priced? i want the motor for the reliability and the cool factor but if this is going to put me in the thousands of dollars price range i would rather just rebuild the stock motor or find another 5.3 setup with all the parts i need. just looking for some input on this before i take on more work than necessary. thanks in advance for any help