1999 4.6 and 5.4 pi heads are they the same?
thank you

 

pi didn't come out until 2000

 

well....I should have explain myself better, i need a head for my f250 with 5.4 and I found a 4.6 pi head, the guy who is selling it claims that it should fit 5.4 just fine, is he right, i would hate to buy something that is not going to fit...thanks

 

the heads are different. between 4.6 and 5.4.

 

The ports and combustion chamber sizes are different between the two engines. The compression ratio would change if you swapped heads. The PI heads were available in early '99, the trucks were built with them, the Expy's and Excursions picked them up half way along in their build year.

-Kerry

 

The heads are the same if they are both PI or both non-PI. Yes they will bolt on and work on either engine.

 

Hey Jimmy... are you saying the heads between the 4.6 and 5.4 are identical? I know they'll swap, but I'm sure the port sizes and combustion chambers are different. To me it wouldn't make sense to put a 4.6 head on a 5.4 unless you had a performance gain.

edit: I found a Fords & Mustangs article about the mod motors... looks like the 4.6 PI actually has a larger exhaust port??? Look here: http://www.mustangandfords.com/techa...ufp_0510_swap/
All else si the same...my fault....swap away.

Part one actually has good info on the history of the motor.

-Kerry

 

Thanks for the replies, so guy was right I can put 4.6 heads on my 5.4, casting number I have on my truck is F75E-6090-C20A I want to put a pi head, I really can really use that extra hp on my f250 crew cab. that was a great article Kerry so I have to stick to head with casting number starting XL3E to make interchange easier between two heads...thanks

 

That's the way I read it... those are the PI heads.

-Kerry

 

The article that I read where a 5.4L was swapped into the Mustang, said that both heads were the same, even the valves and camshafts. They took a PI 5.4L out of a van and put it into a 99 PI 4.6L GT. I think it was Hotrod magazine that did the swap.

Yes, PI heads have different intake ports and larger camshafts than the non-PI heads. And you must use the PI intake with the PI heads. The compression ratio will increase to around 10.0 to 1 if you install PI heads on a non-PI block.
But a PI head is the same on the 4.6L and the 5.4L.

 

I agree...PI is PI and non-PI ias non-PI same for 4.6 or the "larger" one....just make sure your intake manifolds are correct (Teardrop is non-PI and oval is PI).

 

Thanks for all the responses guys, I just need to do something about my 1999 f250 crew-cab, it has 225k miles on it, it’s still running but engine and transmission is very tired, it does not have that much power anymore, it is struggling to accelerate and I’m getting around 8 mpg and I would hate to sell it, it has been a great truck, it did not give me any problems what so ever.

But I don’t know what options to take get a new motor, or just change to pi heads, or is it possible to put a 5.4 3v on it, I already got a new transmission, I just need to figure out what should I do about the engine before I put the new tranny on it, I would appreciate for any input

 

anything you do should involve at least removing the pistons and checking the cylinders for straightness...these things are known for distorting the hell out the blocks due to their running position.Hell, I wouldn't worry too much about the bearings as they usually stand up pretty well but make a point of changing out your oil pump.

 

These mod motors are pricey for rebuilds or new. I'm not too sure that a set of heads will fix the whole thing, either. The 3 valve heads cannot be used with the existing block, that set up has computer controlled variable timing involved.... If you swap a whole drive train (you'll need the tranny, too) with PCM, it'll work. Then you've got the headaches of that swap... grooming the system, getting the thing to run right... not to mention that's gotta cost some buck for that setup.

-Kerry

 

the 5.4 heads are PI from 99-on (ie lightning), the 4.6 truck engines did not go PI until 2001. pre Pi engines will benefit from the increased compression of PI heads and make better HP...these are durable engines, but you MUST change the oil regularly. you can make plenty of power with otherwise stock stuff, it just cost a good bit of money.