As has been stated the block is where you have to center most of your attention. We have a 509 block w/splayed caps. Everything else is just basic small block stuff you have to do to make power on any stock block. Our 406 made 720hp. When you start making big power you will find that it is hard to keep any stock block stable. Blowby, oil leaks, comes with the territory if you don't have a vacuum pump.
Curtis