* Engine Mounts: The engine mounts are likely different, requiring modification or replacement. You'll need to find mounts that correctly align the 3.8L in the engine bay.
* Transmission: The transmission compatibility is crucial. The 3.4L likely used a specific transmission that may not be compatible with the 3.8L. You might need a different transmission, requiring further modifications to the transmission mount and driveshaft.
* Wiring Harness: The wiring harnesses are different. You'll need to either modify the existing harness extensively or source a 3.8L harness, which will require significant rewiring and potentially a new PCM (Powertrain Control Module).
* Exhaust System: The exhaust system will almost certainly need to be replaced or significantly modified to fit the larger engine.
* Cooling System: The 3.8L may require a different radiator or cooling system components due to increased heat output.
* Other Components: Other parts like the air intake, throttle body, and possibly even the steering column might need adjustments or replacements due to the size difference.
In short, while mechanically possible, this swap is a major undertaking requiring significant mechanical expertise and fabrication skills. It's not a weekend project. You'll need a good understanding of automotive mechanics, access to specialized tools, and potentially a considerable budget for parts and labor. It's far easier and likely more cost-effective to find a used 3.4L engine if yours is beyond repair.
