* Engine Management System (EMS): The biggest hurdle. The 1994 engine uses a different computer and wiring harness than the 1997 F-150. You'd need to use the 1997's EMS, which might require extensive rewiring or a custom solution.
* Sensors and Components: Even if the engine block is largely similar, individual sensors, wiring harnesses, and accessories (alternator, starter, etc.) might have different connectors or specifications. You may need to swap some parts from the 1997 engine bay to the 1994 engine.
* Transmission Compatibility: Ensure the transmission in the 1997 F-150 is compatible with the 1994 4.6L. While likely, there's a chance of minor differences.
* Mounts and Brackets: Engine mounts might not be identical, necessitating fabrication or modifications.
In short, while mechanically similar, the electrical and ancillary systems are different enough to make this a complex project. It's not a simple bolt-in swap. It'd require significant mechanical and electrical expertise to make it work. Unless you have significant experience with engine swaps, it's probably best to avoid it and find a suitable 4.6L engine from a closer model year.
