On Ebay Motors, I found a vendor that sells sets of oem F-150 4.6 PI heads with 20 k or less miles, complete with valvetrain, cams, etc. for less than $500 (and that includes shipping). For another hundred per set, they will re-surface both heads. I do not know yet, if that includes the gaskets. But, I do not know yet, if we would need to install oem PI head "dished pistions" to keep the compression down?

Some people I have spoken to have said, "just bolt them on and go" You will see a major increase in power. This included the creator of the Magna charger kit. However, they qualified their statement by saying the Mustang and Thunderbird owners do this all the time. But, it should also be noted that for at least the 4.6 Magna kits, the same intake manifold is used for the non-PI and PI heads with no problems.

Yet others have said, "You MAY need to put in dished pistions to keep the compression down, since the pistions changed when the change was made to PI heads in 2001." Also, if you are considering running or are using a supercharger you MAY need to do this anyway". Some went further to say, you MAY wish to use "stronger" head bolts/studs and the thinner non-PI head gaskets to ensure you do not have leaks/blown gasket with the higher compression. Others continue by saying you MAY also need to get the PI engine intake manifold or have your existing stock manifold or supercharger manifold "match ported" since the PI head ports have a different configuration than stock non-PI heads.

 

Man sure are still a lot of ifs here. Match porting is not a problem. Porting kits are available and I have the tools. Changing over is more involved since lots of things are different in the pre and post PI engines.
I will use very good quality aftermarket head gaskets regardless of what head I put on. I am also going to put headders on so that will fix any fitment problems with the exhaust.

 

So, nobody on here has actually done this yet????? If you didnt switch over the pistons and kept the stock ones, making your compression go up, wouldnt you get a lot of your hp increase just from the increase in compression? But, i do understand if you had a supercharger, then you would want to change the pistons so your compression would be lower.

 

he he ......on the got-pressure site, I made the same comment.... I can not believe that with all the 97-2000 F-150 4.6s out there, someone has not already done this swap!

 

O.K. i'm getting more and more interested in this!!!! if someone finds somebody that has done this (like on a mustang site)can you have them come over here we need some info!!!!!!! I've been wanting/waiting to do this but i thought heads would be alot more$$$....

 

ANYBODY???????

 

......still working on it. I am getting too many conflicting methods of how to do the head swap. I should know more next week. But, I am still amazed that no one can provide some details of the swap

 

iron horse,

We await your information.

From what I have found out so far, the Cams are different between the F150 PI heads and the Mustang PI heads. This is important because most of the PI heads available on Ebay are from Mustang engines. (Note the heads are the same and can be interchanged, only the cams are different).

I think this has been done much more often by the Mustang guys. The only problem is their intake is different then ours.
If you haven't tried at the Corrall web site yet then let me know and I will post it there...

 

WLF,

No, I have not tried on the Mustang sites yet. This morning I am going to start a new thread on fordtruckworld and see if we can get some info there. As well as I have a thread on got-pressure in the "questions about anything" tech. section.

A guy named "Scott" at Allen Engine Development should know. However, he will not be in the office until next week. Also, Flatsman should know, since he did extensive research before building a monster 4.6 engine. He provided some comments in my Magna Vs. thread in the supercharger section, but he knows much more. Therefore, I have emailed him with detailed questions. I should have a response soon. A guy by the name of Johnny Langton was very helpful as well on the got-pressure site.

His thoughts included getting another set of non-PI heads and having them "worked". This way, your compression remains stock with your non-dished pistions , and your assured that your ports all match. Of course, if you do not plan on putting a supercharger with higher boost , the compression issue may not be that much of a concern, since 99 on up 5.4s and 2001 and up 4.6s run higher compression anyway. Yet, the PI engines have dished pistions for a reason. It is to keep compression down

One of the questions I would really liked answered is: If a late model Lightning has a LOWER compression ratio than either of the late model F-150 non-PI and PI engines, does that mean, if you use Lightning heads, you can have a compression ratio lower than stock yet, have an increase in hp and tq due to better flow and will the lightning ports match a Magna chargers manifold ports and stock exhaust manifold

 

Jason,

The PI heads from an L are the same as the heads on a normal 5.4. The reason for the increased CR when using a PI head is the size of the Combustion Chamber. 49cc for the PI and 52 for the non PI head. I did the math a while back but I can not find it, but the CR increase would be about .5 I have a feeling Ford compensated for the increase CR of the PI Heads by using a thicker head gasket for the N/A 5.4s and 4.6s.

JMC

 

Maybe it would be easier to ditch the current truck and get an '03 Lightning. I stopped by the local SVT dealership yesterday and they had a nice , shadow grey, Lightning there. Man I would love to own that truck. They were ready to sell me this one. I was almost ready to buy it! I like my truck though. I like that my payments are reletively low. I think I would be paying around six hundred a month to drive a Lightning and it needs some mods to make it right. For now I'll stick with my old F150.

I don't know what's different in the Lightning heads, as compaired to the standard 5.4 heads. I was under the impression they were the same. I believe the pistons are different as is the bore and stroke. Flats Man is using a set of Lightning heads if I remember correctly so maybe he will have some insight.

I think that JL has given some pretty good info over on got pressure. He seems to be involved with people who really get into these engines. He is reporting decent gains with the PI cams. I think this sounds good. I don't like the thought of ports not matching, or of high compression. I would think that the goal would be to keep our compression at the OE specs.

I think that one of the reasons we can't find a whole lot of information is because these Triton engines haven't been out there long enough. We know we can find tons of information for the 350ci and the 302ci engines but then they were around when the dinosaures were hot rodding. Iron Horse, I think it's exactly what your doing that gets the ball rolling. I'd guess that the aftermarket has many ideas up their sleves but they need to be assured that we will spend our money. So to the aftermarket: WE HAVE THE MONEY SO MAKE US THE HORSE POWER!!!

I have to say it again. These message boards are a great thing. Iron Horse, you are really getting the diolauge going. It just keeps getting better!

 

Jason,

If all you are worried about is the matching of the intake manifold get one from a 2001 or newer truck. As for the heads, take a look at the HP & Torque specs for both the 2003 F-150 and the 4.6 Mustang. Truck torque is 293 @ 3500 and the Mustang is 302 @ 4000. 500 RPM difference. The HP is a different story. Truck is 231 @ 4750 and the Mustang is 260 @ 5250. Again a 500 rpm difference. The problem, more important than port matching, is finding out what the torque curves look like. No one that I know of is working on the 4.6 for truck applications. They are working on the 5.4 L engines. That is where the $$ is. The 4.6 $$ is in the Mustangs. If you can live with the Mustang torque specs then spend the $$ and get the PI heads.

Regards

JMC

 

i've been snooping around too.. Mike T said to "work" my non-pi's also.....

 

Hey JMC!,

So Lightning heads have the smaller "NON-PI" combustion chamber.............but do they "flow" better than a "NON-PI" 4.6 head, meaning......if you installed Lightning heads, valvetrain, cams, etc. on a 97-2000 4.6, you should see an increase in horsepower and torque



Wittom,

Thanks! I plan on keeping this truck long after it is paid for, so I see my improvements as an investment in the .......fun factor! ha!

But, when the price drops much more on used 99 and up Lightnings, and after my current truck is paid for (3 more years!), I hope to see about getting one.... then I will have a fast family truck and a very selfish "all for me" truck

 

Roush,

That is interesting.....If the Lightning guru said to work your non-PI heads, does that mean that the Lightning heads will not work on our 4.6s

Another critical question to ask if you go that route is, what exactly do you need to have "worked" in our heads......one machine shop gave me a price list to choose from. The total of everything that shop could do was well over 1,000 bucks. Of course, I would want to know what is the minimum "work" that would need to be performed to get at least an increase of 20 rear wheel horsepower and torque with an auto transmission


I do not know what everyone eles is wanting to do, but for me, I was looking for a weekend head and cam swap of somekind that got me enough extra hp and tq to make the effort worth it and all for a max. cost of $500 bucks or so