I thought about the same setup (6.0 truck motor), but get the Patriot LS6 (small chamber) Stage 2 or Stage 3 heads and cam setup. They say 500+ HP with that setup on the 5.7 engine. Here's the links:
Heads: http://www.patriot-performance.com/waterNew/default.asp?T=505234&DID=1225
Cam: http://www.patriot-performance.com/waterNew/default.asp?T=507473&DID=1225
Do you know what your chamber size is with the heads shaved .020"? Keep us updated!!!