In the july 04 CHP mag it states that the 6.0 truck intake outperforms the Z06 intake on the LS1. The only one that outperformed it was the F.A.S.T. LSX intake but only by 3 hp and 3 lb. ft. The only drawback that they seen was it was too tall to fit under the f-body's hood. Oh yeah they called it "BIG UGLY"...Zed