450-500HP 360?

You don’t need a power adder to reach your stated goal. Why add the expense, higher maintenance and complexity to your build? I find turbo’s interesting, but I would want to start with a clean sheet of paper if I was to build one. I know guys have successfully run them, but not sure I would start with an LA/Magnum either. They really could use a fifth head bolt. You could go aftermarket block, but not a simple thing. I would probably lean Gen 3.