Tuning with jets, Power valves and an O2 guage

I was looking at the Summit racing site and saw this:


http://www.summitracing.com/parts/hly-0-81870?seid=srese1&gclid=COP_-4CDrLkCFYU5Qgod8VsAzA

The Holley Street Avenger 870 is built with #78 primary jets and #84 secondary jets along with a 4.5 Power Valve.

I thought the Demon carbs were a virtual copy of the Holley except for being a bit more shiny. This Holley has a higher CFM rating but smaller jets and PV ?