I was wondering if they are the same?I have a chance to get a set of either 99 or 2000 5.4 heads(my choice) and was wanting to know if they are the same as the 99 and up 4.6 heads.Any help would greatly be appreciated.What all would be needed if they do fit.I have a 96 T-Bird if that helps bit I also have that 94 Mark VIII short block they will be going on.
Not all 5.4L heads are Performance Improved (PI). If the heads do not have PI stamped on them they are not PI heads. Without the stamp they are the same as 98 4.6L heads or light duty 5.4L heads. You may not be gaining any performance with those heads.
Plus, you may find that your valve covers do not fit the heads. 5.4L motors have the oil fill tub on the right side. In order to make it fit you will have to do what I did. See my web page below for more information.
There is a chance you will need to modify other things to make it work.
The one is a 2000 and the other one is a 99.I am going over Friday to look at them and then I will know exactly what they are.I would have gone over sooner but we are like busy here at work so I have to be here,but Thank You for letting me know what to look for.