Replace 4.6 with 5.4?

[nascartony05]

At work we have a 98 F-150 4x4 with a wore out 4.6. What I am wondering is if anybody knows if we can replace it with a 5.4. If so what all would be involved in such a project. Do we have to replace the computer or should everything work?

[Zack08]

a 5.4l computer, wire harness and vaccumm lines are needed. 5.4 motor mounts bolt right in. I've never done the switch from 4.6-5.4 but my friend has done two. I went from the 5.4 to the 6.8 V10. the mounts are the same the engine was a bit longer so i had to go with an electric fan. it has all the power and torque i need. the engine was cheaper than a junkyard 5.4L. came out of a E350 ambulance and had 15,000 miles on it. got it for $1,200 plus computer ,wiring and vacc. was well worth the 2 1/2 weeks of work and bummin rides

[wafrederick]

The 5.4 is a gas hog if you want to lose your MPGs.Ford does this: .6 month changesIt is horrible job and calls for about 8 hours to change the engine.The intake has to be removed so the engine can come out.