[heavychevy454ss]

The first thing you should do is to remove the restrictive duct that is inside the inner fender. First remove the air tube that goes to the fender. You will see the duct inside the fender hole. Then remove one small screw that is located behind the battery. Then pull like hell on the plastic ducting. It may be hard to get out, just keep trying. Once it is out you will see how restrictive it is. It is way more restictive than anything else in the intake tract.