* TBI System Limitations: The Throttle Body Injection (TBI) system is a relatively simple and less efficient fuel injection system compared to later multi-port fuel injection (MPFI) or even newer TBI systems. It struggles to efficiently manage the increased fuel demands of a higher-output engine. You'll likely experience poor fuel economy, rough running, and potentially significant power limitations even with a more powerful engine.
* ECU Compatibility: The original engine control unit (ECU) is calibrated specifically for the original engine's displacement, fuel injectors, and other components. Swapping in a significantly larger engine will likely result in an inability to properly control fuel delivery and ignition timing, leading to drivability issues and potential engine damage.
* Finding a Suitable Replacement: Finding a higher-output 350 engine that's directly compatible with your existing TBI system will be extremely difficult. Most higher-output 350s from later years will have different bolt patterns, accessories, or other incompatibilities.
* Harness and Sensors: The wiring harness and various sensors (oxygen sensor, coolant temperature sensor, etc.) are designed for the specific engine and TBI system. Adapting these to a higher-output engine would be a complex and potentially expensive undertaking.
Better Alternatives:
Instead of trying to force a higher-output engine into the existing TBI system, consider these far more practical options:
* Engine Swap with MPFI: Swapping to a later-model 350 (or even a different engine) with MPFI is a significantly better option. This will give you the higher output you want with a more modern and efficient fuel delivery system. While still a significant project, the result will be a much more reliable and performant vehicle.
* Upgrade Existing TBI Components: If you're determined to stay with TBI, you could try upgrading components like the throttle body, intake manifold, and exhaust system. However, the gains will be relatively modest, and you'll still be limited by the inherent shortcomings of the TBI system.
In summary, while technically possible to swap engines and maintain TBI, it's not practical or advisable. The cost, complexity, and limited performance gains make a conversion to a later model engine with MPFI a far superior solution for achieving higher output.
