I like what you've done so far. Although LT5 is all aluminum, it still weighs almost the same as old big block, still pretty exotic choice, there was one 65 at Carlisle this year with LT5 and ZF6.
I still preffer the stock body lines over the opened up wheel wells. Here's how a friend of mine solved the problem of how to fit big wheels in a mid year:
Great to see a serious vette project here, keep us posted!