New to the ls platform need some suggestions

[57taskforce]

Ok here goes. I've got a 72 K/20 I'm in the process of restoring. My plan was originally to run thru the 350 and sm465 and slap it back together... well I happened on a 09 Silverado 2500 at work that's totaled. I bought the ly6, complete harness from the whole truck and the 6l90 for $100 total. A few things that had been taken from it to keep other trucks in out fleet running before I got to it include the ecm, tcm, gas pedal and throttle body. What are my options to get this thing swapped into my K20? I'm thinking about using the advance adaptors kit to bolt my np205 to the 6l90. What would you guys with more knowledge suggest I use to make it run? I'd like to keep it fuel injected and swap the cam for some more ponies before it goes in. I build engines for a living so the mechanical stuff is no issue at all for me, I just don't know anything about what's available (or exactly what I need) parts wise.
Thanks guys, Tyler