I have a 98 f150 4x4 with with a bad 5.4 in it... can I put a 4.6 out of a 98 2 wheel drive in it? if so what issues will I have? it looks the motor mounts harnesses transmission all match up?

 

Yep if they are both 1998 engines you can. The difference starts in 1999 PI engines as they have different heads and exhaust is diffrentas well as the intake. Everuthing should hook up fine.

 

Actually any 4six or 5four will work from 97-04. That's using your original PCM, Coil pacs and ECT. No tuning required.

 

Aren't the exhaust farther apart on the 5.4 ?
And the 4.6 for 98 still has two coil packs and plug wires so won't the PCM have an issue with not having 8 little coil packs?

I may be wrong as I have never owned a 5.4.

 

Right, he'll have to get a muffler shop to connect up the exhaust. None of these engines have 8 coil packs, the 5fours never used coil packs.

That's right, he's going from 5four to 4six...so the 98 4six will now utilize the 8 coils the 5four used. The 4six will be COP ignition vs Coil packs....no plug wires for that 4six lol.

 

Nope, I disagree and I don't want to step on anyone's toes, but this is what I found.

I ask these questions a long time ago about these engines and found that nobody knew the answer until I went to the Mustang hotrodders and they knew.
As of yesterday, I have 8 f150's from 1997-2003 4x4's and they are all different engines from 4.6 to 5.4.NPI to PI.
I just placed a 1998 NPI engine in a 1999 PI engine bay and they are not the same for the PCM/ECM wiring harness. I had to change the heads, intake, and exhaust manifolds to make this engine a PI engine so the wiring harness would work. You have an NPI engine in any engine made before 1999 up in the f150 truck 5.4 or 4.6 and the PI 4.6 came later in the f150. The intake on an NPI engine has a butterfly valve on the lower intake that the PI engine does not have as well as the knock sensor has a different plugin and the exhaust hookup to the tailpipes is different and a lot of other stuff. Been there did that one and the best engine to find if you make this change is an engine from an Eddie B Explorer 1998 as that lower half engine can stand over 1000 HP with the PI heads and you go to a 10.5-1 compression from a 9-1.

But it is up to the person who is doing this to make their call. Needless to say, it was eye-opening at what could be done with this engine setup and then set a tune to it to eliminate the bad stuff from the truck PCM/ECM. If you do this with this engine setup it will make a Raptor and other trucks look sick for those that want to know.

 

You got messed up man lol. Yea that's BS.

 

You'll be alright OP.

 

How so? You know I just knew if I answered this question someone would just talk trash and not give an explanation.
You can google about these engines and find out your self some of the things that work and don't work or listen to us that have did these changes.
I run P78 tires on two of my trucks and they spend a lot of time in the mud having fun. They have to be right to do what they do and not BS around.

 

As long as you use your original PCM, all harnesses and proper coils for your drivers.