4.2 to a 5.4Liter ?

[cmcmana1]

Hi, what are the difficulties going from a 4.2 V6 to a 5.4 V8 in a 2003 XL? Is this doable? Any idea on a price range? Thanks

[krewat]

If both engines are available in that truck, then, yes, it's theoretically possible.

Money-wise, that would be something I'd only do in my own backyard, with a complete donor truck in my possession.

It would probably involve the entire drivetrain. Engine, transmission, wiring, driveshafts, maybe even the rear axle if you don't want to blow it up

[gt347sc]

very doable. I did the same type thing on my 94 300 6cyl to lightning 351. Just picked up a wrecked donar so i made sure i had everything i could possibly need. best advice is to keep your donar untill you are compleatly done.