5.4 P71

Let me premise with, I have a 2002 p71. Just about as nice an example as I've ever seen come out of service, turned over 100k last week.

A shop I know has a low mileage 5.4 motor, that came out of a 2005 1-ton van. I could get it for around $1000. 30 extra horsepower, and more importantly 75 more lb's of torque, no decrease in reliability or driveability. Then I started looking around, and first of all I can't find that there's any difference between 5.4's through the years. On that note older 5.4's, like around 2001-2002 age sell for $700 or less on car-part.com. Secondly, it appears as though my heads are the same one's any 5.4 comes with, so all I REALLY would need to scrounge up is the bottom half! (Not to mention 4.6-5.4 intake manifold adapters, probably injectors, and some tuning time at the local dyno).

Additionally, from what I can tell the 5.4 stops making more power around 4000 rpm. Well with the same heads as the 4.6 that makes some sense, but it sounds to me like a set of cams might do a world of good.

Can anybody substantiate any of this and/or direct me to a good resource? Thanks.

Food for thought, 5.7 LS1's and 6.0 Vortec's go for under $1000. As do DOHC head/intake combos for the 4.6.

Also the 5.4 is externally larger than a 4.6 so you may run into clearance problems, especially for the exhaust.

Personally I'm going LSx/Vortec, but I know you want to stay Ford. I think you could do a lot better with early (pre-99) DOHC heads, aftermarket cams, shorties, Cobra intake, and a good tune. With a decent cat-back and your favorite CAI it's probably going to be around 340HP/340TQ for less than that 5.4 plus less work.

The 5.4 is very, very tall. That might give you problems. Also note that the PI heads first fitted to mod motors on the 99 Mustang (other models got these same heads later) have smaller chambers than earlier heads; pistons for use with PI heads are dished a bit. Using early pistons and late heads will produce something like 10.4:1 compression--it won't kill the engine, but it's something to be aware of, especially if you plan on boost. Something you should know about your engine is that it's the exact same hardware as in a Mustang of the same year, and those engines are rated at 260 hp. The difference between the Mustang and CV power rating is in the tune and the exhaust. The van engine is only rated at 255 hp. I really don't think you're going to get much of a performance boost. In my opinion a 5.4 swap is WAY more trouble than it's worth. Just get a good tune, exhaust and maybe some mild cams for less money and more gain than the 5.4.

There is/was a Lightning Tuner that did a switch to a 5.4 in his P71. His name is Sal, and he did own Power Surge Performance. He might be able to help with your questions.I have been out of the loop for a while, but I thing that he is still around.

5.4 fits without too much issue. intake is issue, it is too tall for the hood. The 5.4 with the 4r70W and a 2.73 is a great package. The 110k converter is the way to go.

does the DOHC stuff (heads, intake, etc...) work on a SOHC engine as a complete swap? because i found 2 continental 4.6 dohc engines for 200 each that run.

Yep. Just make sure they match yours (Romeo or Windsor). Stupid Ford's "modular" engine had two different manufacturing designs.

Oh yeah, Continental stuff is FWD and incompatible. You want Mark VIII stuff or early Mustang Cobra (pre-99).

I appreciate everyone's input, but I'm not doing a dohc.

Two main reasons; 1.) I'm not convinced it's less work. Other than the intake manifold adapter that lets me use my lower profile manifold, what else is there? This is not a new idea. I know this swap's been done, and that it fits under the hood. What's the rest of the "work" that makes it not worth it?

2.)The DOHC makes more hp but only slightly, barely, more torque than the sohc. And the dohc 4.6 is 50 lb ft of torque less from the sohc 5.4. It's a big, heavy, 4000lb automatic transmission car. I don't want to rev the piss out of it to get the extra scoot. I want to feel it the moment I put my foot in it. As I said, what with the 5.4 using the same heads as the 4.6 and the powerband dropping off above 4000rpm, I'm convinced all it would take is a pair of cams to out-hp the dohc4.6.

All it takes is a stiff breeze to out-power the 4.6.

The only 5.4 swapped Panther's I know of are in 03+ cars, which have different frames, front cradles, front suspensions, and steering setups. They also have to run compromised intakes to clear the stock hood or add a cowl.

The 5.4 is just as much of a dog as the 4.6. It doesn't breath and it has puny little pistons. If you really want to have more torque you have to swap to a pushrod motor. I know of a P71 like ours with an EFI 351W in it. Like I said, I'm going LSx/Vortec.

Maybe a 3V swap from the 05+ Mustang? All you would need is the heads and intake, delete the butterfly valves, add some cams, and voila!

You understand that all the negatives you just complained about on the 2v 5.4 also exist on said 3v mustang engine, but with added complexity?

so far I've found two 5.4 2v swapped panthers that are 2002 and older. There weren't many details but fitment didn't seem to be a problem. Compromised intake? Can you quantify that statement?

I understand the LS-series is better in every measurable way, I want to be able to pop my hood and have an extremely stock looking engine compartment.

I knew about non-p.i. bottom ends and p.i. heads making higher compression. I wonder if the same is true on the 5.4's? Then all I'd be rounding up is the bottom half of an old 5.4, re-use my 4.6 top half (with manifold adapter), and voila!

I'm gonna prove you wrong about this route damnit!

The 3V is 300/300 bone stock and features heads that flow better than the 4V. It also enjoys the most aftermarket of all the mod motors.

I seriously haven't seen or heard of any pre-03 5.4 Panthers. I wonder how they got them to fit? Two of the three 03+ ones I've read about were sporting the lowest profile intake (a van unit or maybe a Mustang 4.6 setup?) and no hood insulation. The S/C one cut a massive hole in the hood.

Go ahead and try, but I'm already LS shopping. Under my hood will look extremely stock as well, just sorta wrong looking.

I keel you!

http://www.paulshp.com/

^^^ IF ANYONE HAS DONE IT, THEY HAVE ^^^

Contact them and see if it has been done.

bjorkmae on cvn has a 2000 that's done. I'm reading on it now....

Found a complete iron block 6.0 with 4l80e for $1500...

I'd be tempted to flip it for more than twice that and completely finance a 5.3 (at least if I was gonna do what you've got in mind)

Aussie Falcons have run the 5.4 for years and they sell them off the showroom floor with big power check out http://www.tickford.net.au/index.html

I have seen a couple of used 2v centrifugal supercharger setups go for under a grand... That seems easiest of all. I've been thinking of Vorteching my '01 after I finish T45ing it.

good call lugnut. That would be "stage two"

went for a ride in a 4.6 dohc Thunderbird. Felt like driving a stock mark VIII, big deal. Was all the convincing I need to do a J-mod though.

I'm curious about the J-mod. I would like to ride in a so-modded car.

As for me and mod motors, I've had a couple of Cobras and I want some grunt more than I want the revs. I'm tired of wind-up motors. (For now, anyway! Watch, next week I'll come home with an S2000 or something and everyone will say, Huh?)

You know... I have an AMC 401 sitting in the garage doing absolutely nothing, with a 5-Speed setup. 400HP/475FtLbs and there's no emissions here...

No! Bad Mike!

Oh baby that's the dogs nuts there P71

The P71 is my DD so I wont stick it in that, but I am car shopping for something to use it in. I'm thinking 1st Gen Rx-7 right now (not my current one!) to turn into a drag car.