same here. to my surprise when i switched from downey to lc's header, there was a noticeable power difference. LC seems to have done a lot of research on scavenging. i should explain what that is. cylinder one expels its gas and it shoots down the primary header tube, into the collector, and then through the rest of the system. if the primary tubes are all made perfectly, after cylinder ones exhaust has gone through, there is a vaccuum behind it, and the next cylinder expels in to the vaccuum, and it literally sucks the exhaust right out. and this repeats with all the cylinders. this greatly increases exhaust velocity, making more power. now put this with a proper exhaust system, and horsepower, torque and mileage will all increase significantly. an x-pipe (on dual exhaust) works the same way. the LC header does this very well.
erik
