how to achieve 600 to 650 hp sb 408?

The head flow is adequate to support 600 HP, the cam, headers, and compression are not. If you want 650 you are going to need more head flow, .700 lift roller, 2" headers and around 12.5 to 13:1 compression. While the dominator and the Indy intake are good you could probably squeeze another 30 hp out with a tunnel ram and two 750's.