I'm doing the same swap using an ls3 out of a 2015 camaro. What transmission are you going with? I'm thinking of going with a 4l80E and adapt it to the np205. Ive read some threads and most people suggest moving the crossmember forward to accommodate the extra length of the transmission. I also have a dirty dingo engine crossmember I bought a few years ago for the swap. I'm still debating on what controller to use. Holley is at the top of my list because it self tunes but is pretty expensive. Below is an excellent thread from another member.
http://67-72chevytrucks.com/vboard/s...d.php?t=421030