* Engine Management: The 1999 Vortec uses an advanced electronic engine control system (likely OBD-II), while a 1984 vehicle would have a much simpler, likely carburetor-based system, or at best a very basic fuel injection system. You'd need a completely new wiring harness, ECU (Engine Control Unit), and potentially sensors. This is a major undertaking requiring significant electrical knowledge.
* Mounting: The engine mounts and bellhousing are almost certainly different. You'll need to fabricate custom mounts or find adapter plates, and potentially a new transmission adapter if the transmissions aren't compatible.
* Transmission: The transmission from the 1984 vehicle might not be compatible with the 1999 Vortec. You might need a different transmission entirely.
* Exhaust System: The exhaust manifolds and piping will be completely different and will need to be replaced.
* Cooling System: The cooling system components (radiator, hoses, thermostat, etc.) are likely incompatible and will need to be replaced or adapted.
* Accessories: The alternator, power steering pump, and other accessories might have different mounting points and require custom brackets.
In short, this is a very complex engine swap that requires advanced mechanical and electrical skills, plus significant fabrication work. It's not a simple bolt-on project. It's likely far more cost-effective to find a more suitable engine for the 1984 vehicle or rebuild the existing engine. Unless you have significant experience with engine swaps and fabrication, it's best to consult with a professional mechanic.
