It did, and I bolted on mystery heads (as far as porting and flow) because I was tired of sinking money into my car last year. I actually have no idea how much porting was even done, my guess the loser who sold them only polished off the rough cast. cc's for each head didn't match up, not even close so to save money we milled a few thou off one side to get it "close enough", and this took me out of the pump gas range. I think I will swap these heads next winter for pumpgas friendly ones. And he never sent me the intake at all so its a 50/50 rough cast in plenum/runners and my own port matching which aint bad. So for 604.7HP with this combo I was more then please :)
I guess that makes sense if the HP is corrected to sea level, then no matter where you live everyone is playing on an even field. Wonder what I actually get at my 2500', is it that 10.1% less like mentioned and where did that number come from crackedback?
I had an oil leak smoking up the dyno room as well, prolly didn't help my numbers sucking that it.