Instead of just arguing about this back and forth here is some actual research. It looks like you can get to 500whp - 550whp Without spending 15k. Probably will take the same amount of money as a blower only LT1 which makes 500-500 whp (correct me if I’m wrong). Remember these dyno numbers are from an awd car that has this engine so the 400z will dyno a little more.
https://www.infinitiq50.org/threads/...thread.124379/