5.4 heads
 

will 5.4 heads fit a 4.6 and what is needed?

Yes they will. The 99-00 PI heads are the 5.4 heads. I went to McCarville Ford to get a price on them and they have the exact same part#. I know alot of people with 96-98 GTs that have put on ported & polished 99 heads, intakes & valve covers. I'm not sure what is needed, but I can probably get you the e-mail of a few people that have done it and they can tell you. I have heard the 01 engines are made at the Romeo plant so the 01 heads might make your life a little easier.