According to the link below, the standard '97-'98 5.4L engines produce 235 hp & 335 ft-lbs torque.
The standard '99-'01 5.4L engines produce 260 hp & 350 ft-lbs torque.
I understand that mechanically the '97-'01 engines are the virtually the same (modular), but what I don't understand is how the extra HP and torque are produced between the older years and the newer years. I have heard that the tuning has changed over those years to produce more HP and torque on later model years, but 25 extra HP and 15 extra ft-lbs torque? I am looking to do an engine swap and I need as much real life info that I can get.

Can anyone give me any actual facts on this?

Ford F150 Engine Specifications 4.6L 5.4L 4.2L

 

In 1999 the 5.4L motors received PI (Power Improved Heads). These heads probably is what gave the motors the extra gains in horsepower in torque along with some changes to the tune to go along with the new heads.

 

What exactly are power improved heads and how do you identify them?

The reason why I even started this post is because I am doing an engine swap from a 4.6 to a 5.4 and the mechanic doing the work found a 5.4 from a '97 and I didn't want it because of the engine specs and he is trying to tell me the engines are exactly the same and I was trying to argue my point with the link I originally provided.

 

Did 4.6s get PIs in 99 or 01?

 

I just read an article and the Power Improved Heads are exactly what gave these engines the extra HP and TQ starting in '99. I am glad I turned down the '97 engine and opted for a later model.

Ford Modular V-8 Engines Part 2 - Mustang & Fords Magazine

 

PI heads started in 01' for the 4.6. For the SD 5.4's they started in 00'. And for the LD 5.4's in 99'.

Get the newest 5.4 you can get from 97-03 and you will be set if it's a motor that has been taken care of.

 

Some 99' 4.6l got PI heads, some did not.
All 99 5.4l got PI heads. Only 97-98 5.4l had non PI.

 

From what I hear, I'm getting an '01 5.4L...but I haven't heard how many miles are on it yet. The mechanic had installed an older ('97) 5.4L with 71,000 miles on it and I had him take it out to get the '01 5.4L.

 

I put an 02 in my truck with 140k on it. It now has 190k on it and its running strong.

 

Power came from the PI heads (entirely different casting with superior port shapes and a different "fast burn" combustion chamber), new cams (more lift, more duration) and intake manifolds.

Swapping the heads alone will not bring a NPI engine up to PI power levels, assuming everything else stays the same.

 

Probably build more power with PI heads on Non PI engine. if it is properly tuned and runs 93 octane gas.

The pistons are flater on a NPI engine and the heads are dished a bit, the pistions on a PI engine are dished a bit and the heads arnent as much to give an overal same compression ratio on both engines.


But if you run a PI head with less combustion chamber on a NPI pistions your going to raise the compression ratio of the engine while gaining the extra flow and cam of the NPI heads.


I know that you cant run lower octane fuel though.

 

can teh heads from a 99 5.4 be put on a 4.6 or do i ahve to find a 4.6 PI topend to swap mine over?

 

heads are the same for the 5.4l and the 4.6l. They are interchangeable.

 

sweet, there is a nearby junkyard with a 99 5.4 that has a rod knock...

 

Could just get a 97-98 block and a set of the new Trick Flow heads. 4.6 Stangs are seeing 420 FLY wheel HP so I bet the 5.4 should be closer to 460.... which would be pretty sweet. After accesories and drivetrain you may see 350 at the wheels.

But anyway all 99+ Mustangs have the PI heads as well to maybe help widen your search area.
Id imagine the whole C4C thing has killed many nice 5.4s out there.