Interchangeable heads

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Enigma346

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So I have a 2003 Ford Expedition XLT 4.6l. Are the heads interviewed with the 5.4? A buddy has the 5.4 heads. Since I have the replace the valves and all, can I just swap the two heads. The 5.4l is from a 2003 XLT as well.
 

Flexpedition

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I use to follow Mustang forums and this came up a lot. I believe the general consensus was a 5.4L is wider, therefore the heads are further apart. Created an issue with the now too-narrow 4.6L intake.

I'd probably search some Mustang or Ford performance related sites. You get into Romeo vs. Windsor, PI and non PI heads, etc. Deck heights and such. Its not really an answer to your question, but things to consider. Might find the best solution is to rebuild your 4.6 heads if that is whats needed.
 

1955moose

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Apparently the larger heads will fit, but the valve covers are larger. Short of pulling your heads and measuring, the cumbustion chamber, and overall area, your kinda guessing. The depth of the squish area, and so many areas need to be checked. If the 5.4 uses bigger valves, as it probably does, that would definitely be a horsepower plus.

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1955moose

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5.4's definitely do after 04 for F150, and 05 for Expedition. Maybe someone here with 4.6 knowledge can chime in with years of 4.6. I know 04 was last year for the 4.6 on Expeditions, but they continued on for many years in the F150, Crown vics, Mustangs.

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Drae

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The cylinder heads are identical so long as they are both Windsor. Romeo cylinder heads will have differences such as bolt on cam gears and 11 bolt cam covers. A 2003 will definitely not be NPI so no worries there. Here's a nice little reference to use. I have found minor discrepancies in the article but it pertained to what some vehicles got or didn't get.

https://fordcobraengines.com/ford-modular-motor-differences/
 

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