I think so. But still should see some decent gains with bolt ons only. I have a local single cab to me that has full bolt ons including this upgrade and he's running mid 13's. Going to take mine to the track when weather cooperates. I currently have 1 7/8" long tubes, y pipe, 3.5" exhaust and tuned on e85. Going to see what it runs then go back after L86 manifold/throttle body/ CAI upgrade and see what results are to come. Aiming for 13's. Mine is a crew cab though.