[olddog]

By changing to open stepped-tube headers, a tunnel ram intake with 1000 cfm on top, and keeping everything else the same, the Hp peaks at 665 hp in a flat line from 8500 to 9000 rpm and the 2000 rpm torque only drops to 350 lb-ft. However the torque curve is dropping fast as the rpm goes down, so the 1500 rpm torque might drop below 300, lb-ft (not charted).