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Headers are always better, right? To see, we switched to a set of 171/48-inch headers and registered 446 hp at 5,500 rpm, a surprisingly modest gain of only 9.1 hp. The eye-opener was what happened to the torque curve. Though peak torque only rose 4 points, from 491.2 lb-ft at 4,100 rpm to 495.2 lb-ft at 3,100 rpm, note that the peak reading occurred a full 1,000 rpm lower in the curve with the headers. At the same 3,100 rpm, the manifolds were good for 474 lb-ft.