Here's why:
* Size and Weight: The 3800 V6 is considerably larger and heavier than the Beretta's original engine options. The engine bay simply isn't designed to accommodate it. You'd be facing major firewall, hood, and potentially even chassis modifications.
* Transmission Incompatibility: A Muncie M20 or M21 is a completely different transmission than what came in Berettas, and certainly not compatible with the 3800. The 3800 requires a different bellhousing pattern. Adapting this would be a very complex undertaking requiring custom parts.
* Mounts and Accessories: The 3800's engine mounts are not compatible with the Beretta's subframe. You'd need to fabricate custom engine mounts. Similarly, the accessory drive (alternator, power steering pump, etc.) would require extensive modification or custom fabrication.
* Exhaust System: Routing the exhaust around the larger engine would also require significant fabrication.
While technically *possible* with extensive fabrication and engineering skills (and a substantial budget), it's not a practical or realistic swap for the average person. The amount of work would far exceed the value of the resulting vehicle. It would be much simpler and cheaper to use a more appropriate engine swap, such as a GM 3.4L V6, which is a more common and readily adaptable swap for the Beretta.
