Missed on this combo?

First of all : I have ZERO skin in this game. I like to have answers and understand them as well.
I do have one question and one only for whomever wants to answer/comment on it. Flow #'s aside and all that--Why did these heads not produce at least the equivalent of the Hughes? I mean--same cam, more lift (via accurate rockers), slight loss in static comp. How did the Eddy's do as well as they did? Seriously, I would like to know. J.Rob