Unfortold "Carb Spacer" Power?

I run a 1" Super Sucker 4 hole aluminum spacer on my 340, it is all machined and tapered on the bottom side, here is some info from their site.

http://www.cfm-tech.com/HVHdominatorspacersdynotest-1.htm

http://www.cfm-tech.com/nationaldragsterarticlehvh.htm