I have a 99 5.4 in my F350 and I just JB weld repaired a hole in my head (long story). I am trying to determine what heads I have whether PI or NPI so I know what to look for on craigslist or the swap meet. I know that most PI heads have PI marked on them, but mine don't. I also know that PI heads started in 99 but my build date is 6/98 so there may be a chance its a NPI motor. The casting on the driverside head is:

5.4L W Alloy-A
RF-F 5E-6090-C29A
or
RF-F 5E-6090-020A

Thanks in advance for any help.

 

Moved the engine specific forum for specific help.

 

Here's an image of a PI head---without this mark its not a PI head:

 

OK thanks I am going to assume that I have a NPI motor then. I have read about the PI head swap; has anyone done this and had any negative results?