Well, I have more information on the BT heads. The comment given to me was that they are better in every way: flow, combustion, etc. The BT heads flow more at all lifts, and maybe 10% more at high lifts. On an engine, they producted a little more peak, but much more low end.
And that they are more expensive and problematic. Comparing CNCs is different from comparing a stage 2. The CNC cost is maybe a few hundred more for the BT, and the castings are a few hundred more. And of course the Edelbrock has more of an option for using an inexpensive standard head or stage 1 or stage 2 type work.
But that is just the start. They require different rocker stands and different rockers. Both not readily available. The intake will require more porting and some addtional work beyond porting. If you use TD or Jesel rockers, you will need to ensure that a pushrod
oil feed is available.
Net, you have to use some more expensive pieces in addition to the heads. My guess is you will spend $2-3k more for an engine using a set of BT heads.