the flatplane cranks, destroking, all that fun kind of stuff isn't as simple as rod ratios, or keeping under a certain displacement, up in those revs now your changing cylinder wall oiling, required weights, bearing loads, heavily increasin second order harmonics, it's crazy talk if your not looking to spend more than double the price of the car just to develop a block. not to mention now you need to change all the cam profiles spring rates, the timing chain tensioner force, as well as guide placement, it takes race companies years to test and develope something like that, thats why you;ll never see it for us, not enough volume nor money in our market for that. you're best bet would be trying to buy one of the australian v8 supercar motors from a team and rebuild it. even then it's going to cost you buttloads. If this where an ls or an old 350 then the parts are out there but there are over 10million chevy 350's made so the market is HUGE. an old race motor is going to be the best bet for the one or two guys who want and can afford to get a 9000rpm nissan v8 making over 600hp na. look at the falconer engines its only remotely affordable way to get something like that and look at what those cost (epic god awesome bitchin level 11 tho lol)
Welcome to Ryan Falconer Racing Engines! - IRL Street V8 FAQ
I'm sure something is coming for the rest of us who don't have THAT kind of change lying around