My $.02 is go big! 499cid with a huge single turbo say like a 101 - 106mm. Those things are like the size of a 5 gal bucket.

You can run it down around the 10psi mark and make you 1k hp and then if you want turn it up a little an make more. Everyone does small block LSX based twin turbo setups. I want to see something different for a change...