In my wish list making for modding my truck I have wondered how to tell if I have PI heads.
The build sticker inside the door says if I remember right 10/98 so don't know if I have the PI heads or not, if I don't have them how difficult could it be to swap for the PI heads or would it be better to go to a aftermarket head design like Trickflow?

 

Look on the side of the head. Ware the number is it will have PI there too.

The only way your going to move as much air as the trick-flows is with a stage 3 port and bigger valves.
In other words,,,you cant hardly match the power of the Trick-flow heads.

 

Forgive me but where exactly is the number stamped? Pics of where to look would be great if possible.

 

On the driver side valve cover there will be a white decal with numbers on it, post what is there and I will be able to tell you if they are P.I. or not.

 

What are "PI" heads?

 

Right over top of your exhaust header/manifold. On the side of the head.

 

PI = performance improved.
Your truck should have them Jeff.
They started putting them on the 5.4 in 99 and I'm not sure on the 4.6 but I think it was in 2000 or 2001.

 

Cool! Thanks Phil...

 

Couldn't get in to a postion to see the casted numbers but here are the numbers from the white decal on the driver side valve cover as its printed there.

9G876AA
FORD WINDSOR ONTARIO PLANT
982741631
455 10-01-98 54L

Again thanks for all the help so far.

 

Bumped to make sure it doesn't get buried.

 

Dose your 99 have an aluminum intake manifold?

 

9G876AA Is P.I.

 

Yes it does appear to have them.

Thanks for the help Ron.