I seen some I believe they are referred to as power cones in the Dennis Kirk Harley catalog.They go in the exhaust header right at the beginning where they come out of the cylinder head.Suppose to give more torque.Has anybody tried these in the our bikes and if so did they give it any power gains.I see them ranging in price from about $25 to $80.Seems like they might help.There catalog says they help on straight pipes to help give them alittle back pressure.Seems like it could be a lower cost mod if they actually help on our bikes.
