This is completely the other direction than you're going, but a turboed LS1 will get you over 600 horsepower with less cost and be way more drivable. I just watched a video of a stock LS1 producing 633 horsepower with a turbo added, and then still get 25 miles to the gallon.just an option. If you want to stay with the big block, others can help you out more than I can. I don't have the experience to tell you what parts you need.