How can I tell by looking at a V10 cylinder head on the vehicle if it is the new and improved or the 99 style. Thanks in advanced, Dave

 

The 2000+ PI heads will have the letters "PI" on them on the side facing either the rear or the front of the vehicle.

 

Do the PI heads have fully threaded spark plug holes?

 

Ok, thanks. Hopefully I can see down there.......

 

From 1997 untill around 2005 all heads PI or Not only had 4 Threads per sparkplug. Somewhere around 2004 a new Ford casting 1C2E came out and by 2005 was the only 2 valve head in production. These heads (1C2E) had a full set of 8 threads.

 

Just for curiosity sake, looked under the front passenger fender and snapped a pic. Looks like the 1C2E came on my ‘03 F250 V10 w/build date 02/03 (VIN/Door sticker).

 

Use a right-angle dental pick. You can count the threads by dragging it along the threads, and you can tell how far you have lifted the pick as you pull it up along the threads. I estimated I had about 3/16 inch of threads on my 2002 that way..

 

The update to more spark plug threads in the PI heads was made either at the beginning of model year ‘03 or very early in the year, so pretty much any ‘03 or newer 2V 6.8 will have the updated thread count to 7 or 8.