What is a PI Head ?
What is a PI Head ?
What is a PI head and how are they identified?
Junior User
Joined: Aug 2002
Posts: 96
Likes: 0
In a nutshell, PI heads outflow the non-PI heads. The exhaust valve is 2mm larger and the ports are shaped better to allow more air in/out. The combustion chamber is heart-shaped and the intake ports are square shaped instead of tear drop.
Ford started putting the PI heads on the cars in '99 I believe. I think they started putting them on the 5.4 trucks in '99 as well. The 4.6 truck didn't get them until '00 or '01.
"PI" should be stamped on the outside of the head. But you can easily identify the PI head by the shape of the combustion chamber and intake port.
If you scroll down on the below page, I have pictures of the PI and non-PI heads.
PI and non-PI heads
Ford started putting the PI heads on the cars in '99 I believe. I think they started putting them on the 5.4 trucks in '99 as well. The 4.6 truck didn't get them until '00 or '01.
"PI" should be stamped on the outside of the head. But you can easily identify the PI head by the shape of the combustion chamber and intake port.
If you scroll down on the below page, I have pictures of the PI and non-PI heads.
PI and non-PI heads
Cargo Master
Joined: Dec 2004
Posts: 2,232
Likes: 3
From: NE Texas
In the EXCELLENT book: 4.6 Ford Engines by Sean Hyland he indicates that the Performance Improved heads were released in 1999.
He says that a common cause of thread damage in the spark plug holes is removing the plugs while the engine is still hot.
Good luck,
Doc
He says that a common cause of thread damage in the spark plug holes is removing the plugs while the engine is still hot.
Good luck,
Doc
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