NEEDING FEEDBACK AND HELP--engine swap

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Mar 3, 2026 | 10:11 PM

Sicklychaos

Thread Starter

1st Gear

Joined: Oct 2024

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NEEDING FEEDBACK AND HELP--engine swap

hello team,
So I have a 2003 Ford Harley Davidson truck and I also have a 2005 Ford F150 lariat edition. My question to you guys is would it be possible to transfer 03 Ford F150 Harley Davidson truck motor engine and tranny 205 Ford F150 edition What custom changes would I have to make and what would I have to modify for it to be possible for it to work can you guys help me out please? Thoughts feedback I would appreciate it. Thank you so much.

Mar 4, 2026 | 05:15 PM

PupnDuck

Fleet Mechanic

Joined: Jul 2005

Posts: 1,463

Likes: 103

From: Staten Island, NY

I think we need a bit more information:
What engine & trans is currently in each truck?
Is either truck a 4X4?

Some things to think about:
The electronics in each truck is probably quite different. All engine and trans electronics will have to be transferred with its associated engine to the receiving truck. And made to work.
If you live in a state that does emissions testing, that could be a problem putting an '03 engine in an '05 truck.
What's wrong with the engine in the 2005? Would it be better to rebuild the '05 engine or install a re manufactured engine?

Just some things to think about.

Mar 4, 2026 | 05:26 PM

tjc transport

i ain't rite

Joined: Mar 2005

Posts: 65,449

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From: Marlboro Mental Hospital.

if they have 5.4 engines, the 3 probably has a 2 valve engine, and the 05 a 3 valve.different computers i am pretty sure.

Mar 4, 2026 | 08:34 PM

85e150

Super Moderator

Joined: Apr 2004

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I moved you here as the truck getting the engine is the '05. As indicated above, there may be quite a few differences.

This site divides the F150 '97 to '03, then '04 to '08 which signals some major changes and as in almost every case with newer stuff, not just appearance.

What is the condition of the '03? Might be worth more as a running truck than a proper engine for the '05.

Mar 4, 2026 | 08:48 PM

Awar

Cross-Country

Joined: Jul 2025

Posts: 64

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If you need to smog the 05, the 03 engine will never pass. The transmissions are different before 04, 04-08, after that are different also. 05 computer will not run the 2 valve engine, missing variable cam timing on the 2 valve and probably EGR on the two valve. Rebuild the 05 if you want that truck, sell the HD 03 to finance the project.

Mar 5, 2026 | 05:13 AM

torq'ta 5 8

Lead Driver

Joined: Jan 2019

Posts: 5,070

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From: N.W. Alabama

That 03 Ford Harley Davidson should be supercharged, will need to keep computer, that will be fun, going in a 05 with all the new safety garbage.

Mar 5, 2026 | 10:17 AM

Johnny Paycheck

Fleet Mechanic

Joined: Jul 2019

Posts: 1,307

Likes: 310

The ‘03 uses cable throttle while the ‘05 truck will use electronic throttle. So, that’s a big hurdle right off the bat.

The Harley uses two fuel pumps (still a return style fuel system?) while the ‘05 goes returnless fuel system and one pump in the tank.

Just throw a blower on the 3V, get your tuning done and call it a day.

Last edited by Johnny Paycheck; Mar 5, 2026 at 10:20 AM.