Comp cam 212/218 low lift with stock LS6 springs. Most any long tube header, Pacesetters seem to work, ORY mated to a 3" pipe with a magnaflow. Find a tuner, stat. Then look to a stall... 3200 maybe. You'll probably get 300RWHP and it will be a fun, quick truck. When your rear breaks, install a Truetrac and gear for the future of truck. 3.73-4.10s are nice. When that's not enough, buy a turbo. Upgrade injectors, maybe entire fuel system. When your trans breaks, do a 4l80 swap. Increase boost, retune, increase boost again, blow up stock block... at like 950 rwhp. Still have stock intake.