I was just at Hendricks Motor sports and got the behind the scenes shop tour. ( I sell Haas equipment and Hendrick supplies Stewart Haas racing with motors). A full on NASCAR engine goes out the door at $80,000. I heard that from the man first hand. They are designed to last 500 miles between rebuilds. Not what I would put in a street car. That said, the kind of power he OP is looking for will not come cheap no matter how you get it. The car it ends up in will need. To be well built as well. Handling that kind of power takes a lot of modifications to every aspect of a car. As to the twisting a mustang up comment. I had a 65 back in the 70's that I drag raced. The motor was a 289 stock except F4b intake 650 holley, solid lifter 289 HP cam and headers. It was a 4 speed car and I had slicks and 4:57 gear in it. That motor made 300 HP if it was lucky, 260-270 more likely. But it was a light car and with the slicks and deep gears it hooked well. Ran 12.80s. After about 4 track weekends both the rear quarters had creases in them from the stress right in front of the wheel wells. I can only imagine what 600hp would do with out a full cage and frame mods