* Engine Mounts: The engine mounts on an F-150 are designed for its frame, which is different from the Expedition's unibody frame. New engine mounts specifically designed for the Expedition's frame will be needed.
* Transmission: Even if the engine is compatible, the transmission may not be. The F-150 might use a different transmission than the Expedition. If the transmissions are incompatible, a complete transmission swap will be necessary, along with the associated components like driveshafts and transfer case (if applicable).
* Wiring Harness and Computer: The engine's wiring harness and the onboard computer (ECU) are unique to each vehicle. You'll need to either adapt the F-150's harness to the Expedition's system (a complex undertaking) or source an Expedition-compatible harness and ECU. This is arguably the most challenging aspect of the swap.
* Exhaust System: The exhaust system from the F-150 likely won't fit the Expedition's chassis. A new exhaust system will be necessary.
* Cooling System: The cooling system may need modifications or replacements to ensure proper fit and function.
* Accessory Components: Power steering pump, alternator, and other accessory components might require changes or modifications due to differences in placement and mounting points.
* Potential for Body Modifications: Depending on the specific engine and year, there might be clearance issues within the Expedition's engine bay. This could necessitate modifications to the body or firewall.
In short: While parts *might* overlap, a complete engine swap from an F-150 to an Expedition is a significant undertaking requiring extensive mechanical expertise and a substantial investment in parts and labor. It's far more complex than just swapping the engine itself. It's likely cheaper and easier to rebuild or replace the engine in the Expedition with a proper replacement.
