[rcodemach1]

I haven't seen the dyno curves, but my guess is that the powerband is actually widened. So it might come in 500 rpm lower but it doesn't give up Anything on the top. The only way the powerband as a whole could be lowered is if the runners were being lengthened. Some have said that's what the spacer does, but i don't buy that. The spacer might very slightly lengthen the air path (3/8"), but only in the upper plenum and the 6 connecting passages down to the lower plenum. The runners from the lower plenum to the heads are the ones that control the powerband due to their design (length and area).