Will an engine from a 1989 Ford fit and work in 1995 truck?

It depends on the *specific* engines and trucks. Ford used a wide variety of engines across its truck lineup in those years. You need to specify the engine in the 1989 truck (e.g., 302 Windsor, 351 Windsor, 460 big block, etc.) and the engine bay in the 1995 truck (which model of F-series, what engine did it originally have?)

Even if the engine physically fits, there's no guarantee it will work. Consider these factors:

* Engine mounts: The engine mounts may be different, requiring modification or custom fabrication.

* Transmission compatibility: The transmission from the 1989 truck might not bolt up to the 1995 truck's transmission.

* Wiring harness: The wiring harness from the 1989 truck will likely be incompatible with the 1995 truck's electrical system.

* Computer/ECU: The engine control unit (ECU) from the 1989 truck might not be compatible with the 1995 truck's sensors and other components. This is a major hurdle.

* Exhaust system: The exhaust system from the 1989 truck probably won't fit the 1995 truck.

In short: While *some* engines might be swappable with significant modification, it's highly unlikely to be a simple bolt-in affair. You'd need someone with extensive mechanical and automotive electrical knowledge to assess the feasibility, and even then, it might not be practical or cost-effective. You'd likely need a custom wiring harness, new engine mounts, potentially a different transmission, and likely an updated ECU.