PI stands for...
Senior Member
Joined: Jul 2006
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From: Clarksville, TN
For our test, we focused on the 4.6L Two-Valve GT motor circa 1999. Ford took steps to improve upon the original modular motors by offering the Power-Improved (P.I.) versions starting in 1999. The new-for-1999 P.I. motor featured improved breathing courtesy of revised cylinder heads and intake manifold.
Senior Member
Joined: Jun 2006
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From: Maricopa, AZ
o come on, only 6 digits?
guess im a nerd i laughed pretty good at it
guess im a nerd i laughed pretty good at it
Senior Member
Joined: Jun 2006
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From: Maricopa, AZ
that must be what it means in canadian
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Joined: May 2007
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From: Iowa
I though the 5.4L's with PI heads came out in 1999?
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Joined: May 2008
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From: Minnesota
google it! facts are facts. Power improved is most DEFINITALLY a no go. Its Perforamnce improved heads and intake manifold, Hence why both where changed?? Find a mustang forum and ask them if its power improved 
Technical Article Contributor
Joined: Dec 1997
Posts: 9,417
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From: Windsor,Ontario,Canada
Picture this: 100 years from now two old farts rocking on a porch somewhere in the deep south. They are arguing about weather it is a power improved head or a performance improved head on the engine that was in the 1999 F-150 that was found in a barn last month by the first fart's grandson. 
Regards
Jean Marc Chartier
Regards
Jean Marc Chartier
Technical Article Contributor
Joined: Oct 2005
Posts: 25,641
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From: MI
JMC - I bet that will happen.. I can even think of few people that might happen to in the future..
One old man might draw from readings from the Sulivan files. While the other quotes from Babcox.
One old man might draw from readings from the Sulivan files. While the other quotes from Babcox.