That looks good. Roger, I have a question on the crossbar mounting. I am going to make one with dimple die holes but have not determined best way. I am thinking removable clamps from here
http://www.joesracing.com/.
However your idea looks good with sheet metal extending all the way to bars. Are you just using a couple of 3/4" bars with flat tabs?
Oh and John....I have a new crate LS3 and I also can deliver for the swap