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would 5.4 heads work on a 4.6 i just thought bout it. it might be a dumb question i don't know if they would work or not just curious. also would these then be better then pi 4.6 heads if they work?
 

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in the 2V NPI sense, 5.4 heads are identical to F5 4.6 heads--they are literally the same head

in the 2V PI sense, the 5.4 heads are identical to the 99-04 mustang PI heads---they are literally the same head
:zwthstpd:
 

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oh ok. i thought there might be slight differences but obviously not. thanks for the info guys
 

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this question kinda goes along with this question. on some off the 5.4 pi heads (Truck) cam profiles alittle more aggresive than the mustang 4.6 pi heads? i was told this by some one but i wasn't really for sure. cause i've been trying to sell my pi cams that cam out of 5.4 truck
 

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There were many different head p/n offerings. Depending on the year. At one time I had a list but I can not find it at this time. Basically 98-99 was a transition year for the 5.4L heads. You can get both PI and NPI heads. The cams were mostly the same for the head style. :)
 

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Really I would have though that they would have larger ports but I'm not very familiar with the 2v 5.4 heads. I do know that the later 32v heads used on Navigators while very similar to 03/04 4.6 32v heads have larger ports because of the increased displacement of the 5.4. I am pretty sure the 99-02 5.4 32v heads most likely have larger ports as well but don't qoute me on it. If your looking for 32v then don't stick em on a 4.6 then might do ok on a stroker or bigbore though. After all the FR500c race cars rune the larger port Ford GT style heads on a BB but again this engines are most likely sluggish at low rpms but scream in uppers where then need all that extra air.
 

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Really I would have though that they would have larger ports but I'm not very familiar with the 2v 5.4 heads. I do know that the later 32v heads used on Navigators while very similar to 03/04 4.6 32v heads have larger ports because of the increased displacement of the 5.4. I am pretty sure the 99-02 5.4 32v heads most likely have larger ports as well but don't qoute me on it. If your looking for 32v then don't stick em on a 4.6 then might do ok on a stroker or bigbore though. After all the FR500c race cars rune the larger port Ford GT style heads on a BB but again this engines are most likely sluggish at low rpms but scream in uppers where then need all that extra air.

the 2V PI heads (romeo and windsors) are pretty much like a '1 size fits all' deal that were used on both 4.6s and 5.4s....you're right in that the navigator (5.4) heads have much bigger intake ports compared to 4.6 tumble-port heads....so the DOHC vehicles did indeed get a more vehicle-specific head designation
 

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Be careful with 5.4L heads built in 99. In the past people have stated that all 5.4L heads built in 99 were the newer PI style. However, Ford offered both power improved (PI) and non-power improved for the 5.4L for the Windsor head bolt pattern. They called them light duty heads and they came with round "Romeo' Style ports.

To make sure you are getting what you want look for the letters "PI" stamped into the casting.
:cool:
 

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the 2V PI heads (romeo and windsors) are pretty much like a '1 size fits all' deal that were used on both 4.6s and 5.4s....you're right in that the navigator (5.4) heads have much bigger intake ports compared to 4.6 tumble-port heads....so the DOHC vehicles did indeed get a more vehicle-specific head designation
That definitely explains why the 2v 5.4 run out of power real low in the rpm range, well that and the mediocre flowof the PI’s they’re OK for a 4.6 but just don’t cut it on a 5.4. Thanks for the clarification.
 

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actually it's not even that....the valves are too close to the outer edges of the combustion chamber/cylinder walls.....this is called valve-shrouding.......neither PIs nor NPIs are adequate for a 4.6, let alone a 5.4........this is why there are huge gains when people go with 3.7" big-bores in aluminum blocks with PIs or NPIs
 

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actually it's not even that....the valves are too close to the outer edges of the combustion chamber/cylinder walls.....this is called valve-shrouding.......neither PIs nor NPIs are adequate for a 4.6, let alone a 5.4........this is why there are huge gains when people go with 3.7" big-bores in aluminum blocks with PIs or NPIs
Yea tell me about it I've been saying for years Ford should have gone with a 3.7 inch bore from the start but no they wanted to mount these things transversely for FWDR applications so they had to limit their freaking bore spacing. Wow look how that ended up Lincoln Continental oh wait they haven’t made that thing in years. They really should have worked a little harder on the 2v’s think about it PI heads don’t even match GT40’s in flow plus the valves have a crapper shot at the combustion camber because of shrouding. The worst part is even the 3v's aren't good enough on a 5.4 the only way to go with them is the 32v's.
 

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My stock 5.4L crank/ rods can rev just as high as a stock 4.6L crank/ rods. In fact my peak HP ends up close to the same RPM (4,700 to 5,000) as an equal 4.6L. I doubt that there will be much of a difference if you add better heads (that I can not afford) with 4.6L cams.

Not until you add a set of cams that are designed to take advantage of the clearance between the pistons and the valves on the 5.4L to some high flow heads would there be a difference. This is one of the trick$ the big boy$ use. :rolleyes:

PS: You should come to our car show in Morrisville April 25th. I will show you my 5.4L!
 

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My stock 5.4L crank/ rods can rev just as high as a stock 4.6L crank/ rods. In fact my peak HP ends up close to the same RPM (4,700 to 5,000) as an equal 4.6L. I doubt that there will be much of a difference if you add better heads (that I can not afford) with 4.6L cams.

Not until you add a set of cams that are designed to take advantage of the clearance between the pistons and the valves on the 5.4L to some high flow heads would there be a difference. This is one of the trick$ the big boy$ use. :rolleyes:

PS: You should come to our car show in Morrisville April 25th. I will show you my 5.4L!
I don't know that's a pretty far drive for me across the ENTIRE Delaware river and all lol. I work alternative Saturdays so I'll have to see which one it falls on but I love car shows and definitely would like to see your 5.4 set up.
 
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