v6 swap to a 5.4

wheelyman19 said:

HI everyone, ive been thinkin bout doin a 5.4 swap into a 99-04 v6 and ive looked through many threads and nothing really answered wat i wanna kno. so ive done a v6 to 5.0 swap on a 95. and i was wondering if this swap was simular in difficulty. and wat exactly will i all need for the swap. like when i did the 5.0 swap the harness was able to be swaped right by the front head light area and was wondering if itd be the same on 99-04 car. cause from wat i got if u use a gt that pretty much all the wireing connects right up and wat tranny would i use? one from a gt or wat. and id get a gt tach swap out the rearend and ****. and i dont wanna get a gt cause i just brought one to the junk yard after my head on collision and had my fun but wanted more and i liked the enjoyement of the 5.0 swap and am hoping it isnt much harded to do the 5.4 thanks for all the help in advance!!!! lol

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Before I continue (you probably already know this) - this is tons of work and a million people including myself will tell you to just go and buy a new GT. But if you want the info this is what you should do. The way I would think about it is first the swap to a v8, than what is needed to fit the 5.4.

Also so you know in general terms a 5.4L is just a stroked 4.6. It is heavier, taller, wider, and the most common 5.4, the 2V, will produce roughly the same power NA. If I were you I would swap in a 4.6L or buy a GT. But the 5.4 swap is very similar and if that is what you want to do, it is unique and why not. The motor you get will most likely be a truck motor and the cam will be optimized for towing.... but that can all be switched out....

The below will work for a 5.4L 2v (must more common and budget friendly): (The 4v requires a couple extra switches but will produce more power...)
Start:
99-04 Mustang 3.9L V6

Recommendation...... Donor Cars
5.4L V8 (Many options- F series trucks, E series vans, etc)
99-04 Mustang 4.6L Gt (Junker- your old GT would be really helpful here.... at least for a couple things, another donor with more front end parts would help too)

New parts:
-Motor Mounts
-Professional Products 54110: Professional Products Intake Adapter Plates
Professional Products 54110 - Professional Products Intake Adapter Plates - Overview - SummitRacing.com
-oil filter

From a GT:
-Wiring Harness, ECU
-Headers (shorties only!)
-Transmission & trans harness (if your GT was a manual-you may need to get a different flywheel depending on what year your GT was, if it was an auto than a transmission cooler would help)
-Rear Axle (8.8" rear)
-Midpipe (this will have to be widened in the front to fit the 5.4)
-Catback
-Air intake, TB/plenum, intake manifold
-K Member
-Radiator, Hoses, Overflow Tank
-All motor accessories (unless they come with the 5.4): Starter, waterpump, alternator, hydrobooster/vac lines, coil packs and wires, a/c compressor and lines
-Dash Gauges

Recommended changes to the motor:
-New set of cams (your pick)
-(recommended but... optional): Forged rods/rod bolts/pistons


This list is probably ~95% complete. If anyone has anything else feel free to add to the list or correct anything above.