To get within MAYBE 20rwhp of 400rwhp you would need a big cai(like C&L Racer),93 octane tune, Mufflers, High Flow Mid Pipe & Cats, UDP's, CMDP's, LT headers, aluminum driveshaft, Stg. 3 Comp Cams, Stg. 3 Livernois Heads, and lots of dyno tuning. Also instead of waiting for the FAST intake manifold to come out,you could go to a shop who knows what they are doing and get your intake manifold ported.
To get within MAYBE 20rwhp of 400rwhp you would need a big cai(like C&L Racer),93 octane tune, Mufflers, High Flow Mid Pipe & Cats, UDP's, CMDP's, LT headers, aluminum driveshaft, Stg. 3 Comp Cams, Stg. 3 Livernois Heads, and lots of dyno tuning. Also instead of waiting for the FAST intake manifold to come out,you could go to a shop who knows what they are doing and get your intake manifold ported.
LOL! Why would I need an aluminum driveshaft to make HP? Funniest thing I have ever heard.