If you add Callies Compstar connecting rods and Diamond pistons, along with Total Seal rings to a machined block, you will have a bottom end that can handle 700 rwhp all day long. I'd shoot for a 9.5/1 compression ratio, the pistons need to be ordered for the cc of your heads.
Two Walbro fuel pumps in your fuel tank will support 600 rwhp, and will help to keep cost down. If going used, I'd look for an ATI ProCharger D-1SC 1GJ204-SCI 8 rib kit. This kit will easily handle your requirements without any hassles.
Check out this Corvette that has the above mods on it, and makes 740 rwhp and is out practicing on a road course for at least several hours every week, and still gets 28 mpg. http://www.exoticperformanceplus.com...Car.php?car=40