Good article - though for sure head flows leave us guessing a little. I just cleaned up the Edels in the Gonkulator and it said
Torq 505 at 4700
Powr 551 at 6500
(To compare, you have to knock about 7hp off their results since they weren't driving the water pump)
Still, close enough given what we know and don't know.
Note the Gonk also feels like 6000 is way low for a peak.
A 950 Holley gonks about 17hp more, if that is really 650cfm at 1.5", wow, that's a small block carb!
The picture of the heads shows a heart shape chamber, doesn't look like the good old 1990s Edelbrock vintage, did I miss something there?
They don't say much about the heads other than that picture.