Black99f150

HI my name is Matt I have a 99 f150 4.6 automatic. I seen some guys were converting the none PI motors into PI motors. So my plan is to swap heads and intake from a 2003 f150 4.6. I also read that you should change cams as well, is this correct? If so I want to use comp cams but I'm not sure what I should use. Any help is very appreciated thanks guys.