* Engine Mounts: The 5.3L Vortec and the 350 likely have different engine mount locations. You'll need engine mounts designed for a 5.3L in a 1997 Tahoe, or possibly custom mounts fabricated.
* Transmission: This depends on the transmission in your Tahoe. If it's a 4L60E, you might be able to use it with the 5.3L with minimal adaptation, but a professional inspection is needed. Other transmissions may require more extensive changes or a complete swap. The 4L60E is the most common transmission in those years.
* Wiring Harness: The 5.3L Vortec's wiring harness will be different. You'll likely need to either adapt the existing harness or use a harness from a donor vehicle (a similar-year truck with a 5.3L). This is often a complex task requiring significant electrical knowledge.
* Computer (PCM): The engine control module (PCM) from the 5.3L donor vehicle is necessary. You'll also need to program it to work with your specific vehicle.
* Exhaust System: The exhaust system will need to be modified or replaced to fit the 5.3L.
* Accessories: Consider the alternator, power steering pump, and air conditioning compressor. They may or may not be compatible and might need to be swapped with parts from the donor vehicle.
In short, while it's *possible*, this isn't a beginner-level project. It requires mechanical expertise, specialized tools, and potentially a significant amount of time. It's advisable to seek the help of an experienced mechanic or engine builder. They can assess the specific challenges involved with your Tahoe and guide you through the process. A junkyard or parts supplier that specializes in GM vehicles can be useful in sourcing the necessary parts.
