Here's why:
* Size and Weight: The 389 is a very large and heavy engine. The Duster's engine bay is relatively small and wasn't designed for an engine of that size. It would require extensive firewall modifications, possibly even modifications to the body structure itself.
* Mounts and Accessories: The engine's mounting points and the placement of accessories (alternator, power steering pump, etc.) are completely different from a Duster's original engine (typically a slant-six or small-block V8). Custom mounts and potentially custom fabrication of accessories brackets would be necessary.
* Drivetrain Compatibility: You'd need to address compatibility with the Duster's transmission and drivetrain. This might require a custom driveshaft, modification of the transmission tunnel, and potentially a different rear end.
* Exhaust System: Routing the exhaust system around the larger engine would be a major challenge, requiring custom fabrication.
While some extremely dedicated and skilled fabricators might *theoretically* accomplish this, it would be a massive undertaking requiring significant custom work, expertise, and expense. It's far beyond a simple swap and likely wouldn't be practical for most people.
