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any PI heads will bolt on to the 5.4 block.....but you have to have the right valve covers for your ported heads...romeo valve covers are different from windsor valve covers
 

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Discussion Starter · #3 ·
right. i have my ported pi heads and my valve covers off my gt. I just wanna out them on the 5.4. Will the compression ratio be the same?
 

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Discussion Starter · #5 ·
So if I use my 4.6 heads and my 4.6 intake, I will still need adapter plates? i thought you just need the plates to put the 4.6 intake on the 5.4 heads.
 

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Discussion Starter · #7 ·
what do the plates exactly adapt? Is it since the heads are spread farther apart due to the wider block?
 

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Breaking ****
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what do the plates exactly adapt? Is it since the heads are spread farther apart due to the wider block?
Exactly. the intake isnt wide enough to reach from head to head on a 5.4 block. Adaptor plates are a must, or get a 5.4 intake
 

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the same as any engine would, they love it. lol
What he said,
Depending on the generation 5.4 you simply add displacement to the current setup. That should give you a ballpark on power output.
 

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Discussion Starter · #12 ·
not really. i have no idea how these 5.4's respond. I mean, they come out of a truck. are there anything stronger about the motors?
 

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Besides the intake issue whether using the intake spacer and a premium PI aftermarket intake like a logan or P-51

or the very iffy HPS 5.4L intake (if it is anything like the 4.6L intake)

what other steps needed to be done to transfer a 5.4L short block into a 96-2004 GT application?

motor mounts? flex plate or flywheel? or clutch etc. crank sensors cam sensors?

In the past the intake was always the deal breaker in the swap so it was never an option for me.

also anyone know of the weight difference? or if the block being wider does it affect exhaust manifold locations as well or is the difference so slight that it will not affect the exhaust manifolds.

Don't mean to highjack the thread since all these are pertaining to the swap and something overlooked might come up.
 

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I can tell you from experience... I've done this swap already and love every bit of it. One of the biggest misconceptions a lot of people have is with the differences between the 4.6 and 5.4 engines in general. They are the exact same engine... read this again they are the same engine. The only difference is that the 5.4 has a higher deck height to accomodate the longer stroke. Other than that, every bit of the blocks are the same. The trans & all accessories bolt up like normal. What does this mean? 5.4 and 4.6 engines use the same heads. But because of the additional deck height, the heads on the 5.4 are ultimately spaced further apart than they are on the 4.6. That being the case, in order to reuse your PI intake manifold, you need to use adapter plates. Here is a picture of my 5.4 on the engine stand with the adapter plates:

And here is what all of it looks like buttoned up in the engine compartment:

I just pulled the trigger on the new HPS intake manifold for the 5.4L, so i no longer have a need for my adapter plates. (PM me if you are interested in buying them)
As far as compression ratios, the 5.4 has more deck clearance than the 4.6 (0.120" vs. 0.008"). So, with using the PI heads, a NPI 5.4 short block will have a 9.5:1 CR, and a PI 5.4 will have 9.0:1 CR.
The one other thing you will need to do is have your H/X pipe modified to be wider. Once again to mate up to a wider engine.
As far as power production and capability, it is every bit as capable as the 4.6... with one exception... TORQUE! My 4.6 combo made (at the wheels) 250hp/280tq... That same combo on my 5.4 made (265hp/330tq)... that was +15hp, and +50tq.
 

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Exactly how was the X pipe modified? I mean is the difference so slight that you could bolt up one side and apply heat to the pipe and coax it to bend slight enough to bolt in?

Or does it involve more work?

I ask this because in the event of major alteration I would not want to have to tow the car to a muffler shop.
 

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also are those adapter plates custom made or are they the ones that can be purchased? because they look kinda on the thick side?

looks to be almost 2 inches high? that works with a stock hood?

thanks for the info in advance.

seems to me a 5.4L short block is a viable alternative now since the whole intake issue is resolved.
 

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So I could throw my old PI heads on the old lady's '03 Expedition, and it'll be hot to trot?
 

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03s are still two-valve heads, right?
Hot to trot!
Yep. I just thought that might give the 5.4 some extra umph when we're hullin' the stang from track to track. Now the kicker is seeing if the funds will be there for the heads for my car.
 

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Exactly how was the X pipe modified? I mean is the difference so slight that you could bolt up one side and apply heat to the pipe and coax it to bend slight enough to bolt in?

Or does it involve more work?

I ask this because in the event of major alteration I would not want to have to tow the car to a muffler shop.
The adapter plates are 1.25" thick, and yes it allows everything to still fit under a stock hood. (They are for sale BTW). As far as the x-pipe goes, I have a welder, so I was able to cut and weld it myself.
 
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