The 20 to 30 was from the people that I knew that had the cam done. I'm talking about just a cam swap, not including air box, headers, ls6 intake, etc.. Yeah if you do all the bolt-ons you'll put down 360 to 380. My buddy with a air box, catback and hotcam put down 360 with stock manifolds. I've never got around to taking mine to the dyno. I figured it'll put down about 360 because I don't have the ls6 intake.