600hp at the wheels on a stock block is really pushing it. That much power on a stock will probably crack it. There are a few people who have done it, but not with any sort of reliability. Most of them did it with high end turbocharger kits, and didn't rev the engine up much. If you really have your heart set on making 600 to the wheels, then you really need to step up to an aftermarket block, which is going to run you a little over $2K just for the block. If you are willing to settle for about 500 to the wheels, then you can get away with a stock block. There is another member here, Pops Fun, who used to have a 500rwhp stock block engine. He is now running an aftermarket block. His stock block motor blew a piston, but the block itself didn't crack. I believe Pops Fun had a stock block 347 with AFR 185s and an S-trim. Given that you want to run a blower, don't go crazy spending money super duper heads. You should be able to make that kind of power with a blower, and a mid range Aluminum head. Something like an AFR 185 or Twisted Wedge, or the mid range RHS head. I think the RHS is the most affordable. As long as it has a 2.02" intake and 1.60" exhaust it should suit your needs.
Kurt