I like big boss's plan. As everyone here knows, the biggest limiting factor are the heads. I also have a low compression, big displacement engine with a cam that is a little milder (KC's 252/262 duration). The only thing the engine doesn't do well is rev off idle. If that's real important, you can always run 20-degree initial timing and use a retard box.
Unfortunately, you need to port the head and the manifold. You need at least 300 intake cfm in a big motor. KC's Stage 2 heads are close I think.
I know that it's taboo here, but nitrous would realllllllly wake this motor up. My motor is street-friendly - I drive it at 1,500-2,000 RPM's all day, and it still has a little over 725 HP when spraying. You need to plan ahead a little before getting on it.
I am not sure if you can pull the cam with the engine in the car. If you can, I would run the cam as it is and go back later.
The information from concobra is right on and we are lucky to have him among us.
Good luck.
Brian