Ok, this [pic] is just the beginning of what it cost, and takes, to get 500HP. Add another 75% on that, throw in machining, and I did all the work. Add ??? for labour. You can get 500 HP and more out of a 400, but it costs $$$$ and may not be good on the street. But if that's what you want, go for it. I don't want to be the only one with more in the engine than the car will ever be worth.
Fun though!