Jim, I will back my "claim" again, we switched the springs in those heads quite a while back, and have not updated the listing online. Take a valve cover off and see for your self if you dont mind, it is a chome dual spring rated to .690 lift just as I told you in my e-mail, when I mailed you your chart.
Uncertain of your valve train noise, they do get louder with larger cams, you do still have stock lifters.
As for your power output, I believe that to be inline with comparables, (we have used that same cam and head package on a few cars, LS1 , and LS2).Similarly from a LS2 Vette (Antony's old vette), manual with a ported throttle body, kooks long tubes, same cam, same heads, and a 3.57 gear which is stock I believe, versus your 4.07 I believe or there about in the Mazda rear end ; that ls2 vette made 437 wheel horsepower, deduct say 5-7 percent for the auto and stock converter, 437 deduced 7% puts us at 406 wheel horsepower, then a bit for the rear end gear differences, and the bigger LS2 motor kooks, TB, ect. So again I think your power is certainly in the correct range.
As for the speed density, that is a whole another issue that has been gone over by un-educated people several times in CR, and I believe there isn't a need to go over it again in this example.
Regards
http://www.ipsmotorsports.net/pictures/Brandon%20Photos/Anthony%20gray.bmp