Notices
2004 - 2008 F150 2004, 2005, 2006, 2007 and 2008 Ford F150's with 5.4 V8, 4.6 V8 engine
Sponsored by:
Sponsored by:

replace 2008 4.2 with a 2003 4.2, will it work?

Thread Tools
 
Search this Thread
 
Old Mar 4, 2026 | 08:56 PM
  #1  
051's Avatar
051
Thread Starter
|
Cross-Country
15 Year Member
Joined: Apr 2010
Posts: 98
Likes: 7
replace 2008 4.2 with a 2003 4.2, will it work?

I have a good 4.2 in a wrecked 2003 f 150. Looking at a 2008 that has a bad 4.2. Thinking of buying the 08 and putting the 03 engine in it. Is this a direct fit? Both are automatic, 2wd, extended cab.
Any advice is appreciated.
Thanks!
051
 
Reply
Old Mar 5, 2026 | 10:14 AM
  #2  
Johnny Paycheck's Avatar
Johnny Paycheck
Fleet Mechanic
5 Year Member
Liked
Loved
Community Favorite
Joined: Jul 2019
Posts: 1,323
Likes: 314
You will have to swap stuff. After 2000, it’s the same base blocks. Obviously, the intake is different, alternator I believe as well.



I think this video will outline differences over the years. I was looking at swapping an ‘08 4.2 into my ‘03 when that time had arrived, but I lucked out and found another lower mileage ‘03 engine instead.
 

Last edited by Johnny Paycheck; Mar 5, 2026 at 10:16 AM.
Reply
Old Mar 6, 2026 | 08:28 AM
  #3  
051's Avatar
051
Thread Starter
|
Cross-Country
15 Year Member
Joined: Apr 2010
Posts: 98
Likes: 7
Thank you!
051
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
2001gocougs
1997 - 2003 F150
1
Apr 9, 2008 07:57 AM
gamecock
1997 - 2003 F150
2
Jan 21, 2004 02:16 PM
rfields84
1997 - 2003 F150
3
May 23, 2003 10:41 PM




All times are GMT -5. The time now is 02:13 AM.

story-0
10 Ways Ford is LOSING to the Competition

Slideshow: 10 ways Ford is losing to the competition

By Joe Kucinski | 2026-06-15 09:52:01


VIEW MORE
story-1
Top 6 Best Deals Available on New Fords & Lincolns Right Now

Some great targets in today's expensive world.

By Brett Foote | 2026-06-15 09:35:19


VIEW MORE
story-2
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level

Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.

By Verdad Gallardo | 2026-06-12 11:01:55


VIEW MORE
story-3
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-4
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-5
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-6
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-7
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-8
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-9
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE