What is a good combo for turning high rpm?

Just some random thoughts... But if your goal is 400ish horsepower building for 8000+ isnt feasible. You will be making much more than that if you need power up at that rpm. Also, the budget needs to be larger. You can't do a decent long lived package IMO for $7K. The top end is going to cost you 3-4K, and the crank will run another $1500+ unless you find a decent one second hand. It might make sense to buy a used up P7 or W9 engine and de-tune it, but event hat's going to cost more than $7K and you'll need custom headers and possibly custom engine mounting. If you stay with an LA based engine, I'd stay conservative on the stroke, lighten the bobweight, plan for oiling and cam mods, and big heads. I'm not sure you can get an LA done that will live up there for $7K. Rev it, yes. Make power and be usable up there... I don't think so.