Blown engine swapping npi and pi???

From what I looked up over the past few weeks. using PI heads, cam and intake on a NPI engine makes the most compression and the best power combo. It appears with these 4.6 2V engines the cams only push the power further up the RPM range and thats fine but they do lose a little on the bottom and there isn't much there to begin with. The best bang for the buck seems to be a Coyote swap or slap on a supercharger for good power.

There is a Youtube video showing every combo and the power it put out on both PI and NPI combos. If I can find it again I'll post a link

As far as airflow goes, there is little difference between PI and NPI heads though; the real difference is in the combustion chambers. For me, the main consideration is intake options, for which there are none that match an NPI head. You can try and get a PI intake on there, but I had nothing but coolant leaks when I did (using the RTV method), so you will never see me messing with NPI heads and PI intakes again.

Ford made millions of PI engines, as late at 2014 in fleet vehicles. I commonly see them on eBay from auto recyclers in the $600-700 range, with shipping and a warranty included. That is the route I would go; you might be able to get an NPI engine a bit cheaper now, but you're likely better off in the long run (if you intend to do anything more with this engine).