So my dad bought my Great Uncle's 98 XL 150 Supercab 2x4. The minute he did engine blew up so they put a new motor in it. That was about 16 years ago now and I'm working on the truck trying to get it fixed up so we can keep it in the family. I have a plan for most things but down the line I want to swap out the motor for a newer more efficient motor. The goal of the truck isn't a ton of power literally any of the Ecoboost models would be a big jump in horsepower from what's in there. But it would also be a heck of a lot more fuel-efficient an increase of 4-5mpg in the city alone. So here's my big ask of the community because I can't find info on if someone has done it and whether or not it would be a crazy fabrication process, but I want to swap out the 4.6 and the trans and likely the rear axle and diff for a stronger one and but in the 2.7L Ecoboost. The current truck is already automatic so I'd like to just move the 10 speed into the truck if possible.
Any advice would be helpful this is my first serious build. I've maintained my cars in the past but never gotten this deep into a build so I'm in deep waters and just looking for some knowledge.