Ya they have been doing the cam thing for along time now, our corrected altitude on a typical summer day can be over 7,000 feet. I have not cnc'd the heads but this winter I am planning to port, polish, and gasket match my self, I have not had a single problem or complaint about these pro comp heads they were affordable and work well "so far". I to am running the smaller header tubes I dont have them money for the bigger ones they would have to be customn made to fit in my car. I know I will be hurting in that area if you bring big air in you have to be able to let it out. I shift the car at 7,000 rpm's and run through the traps at about 7100, or 7200 rpms now. I am concerned about the 4500 low end on that cam im afraid it might bog the car down off the line and loose my 60 foot I have been considering a 3800 to a 3500 / 7000 rpm cam to help gain 60 foot times what do you think?
This is a tuff decision and an expensive one I dont want to get this wrong.