[Keithc8]

You have to decide what budget you want to spend on the engine. Then you will have to decide on the parts to use that will fit your budget. It is no problem with todays parts and tech to do a 600 HP engine that will run up to 6000 rpms and do fine for a long time.
Again it comes down to what you want to do with the engine and what you want to spend. You get with the right person and design the engine for your application. You can do it with a 390 block and one of the stroker cranks and get the power you want with no problem. If you want an original 427 block that is where the hunt and finding a good one makes it a little harder and will cost you more money. There are new 427 block options but that will add about 3500.00 or so to the cost over a 390 block.
Doing an FE engine to do what you want is no problem. Just get what you want and you will be happy in the end.

Good luck, Keith Craft