* Block Design Differences: There were changes in the block casting over the years. The 1997 block likely has different bolt patterns for accessories (alternator, power steering pump, etc.), different oil pan design, and potentially different lifter designs or even bore spacing.
* Computer Control: The 1997 engine likely uses a computer-controlled ignition and fuel injection system. Your 1984 truck likely uses a carburetor and a simpler ignition system. Integrating the 1997 engine's computer system into the 1984 truck's wiring harness would be a significant undertaking and potentially impossible without extensive modification or a new wiring harness.
* Transmission Compatibility: The transmission must be compatible with the engine. The bellhousing bolt pattern might be different, requiring a different transmission or adapter.
* Exhaust Manifolds and Headers: The exhaust manifolds or headers from the 1997 engine likely won't fit the 1984 truck's frame and exhaust system.
In short: While the engine *might* share some similarities, the differences are substantial enough to make it extremely difficult and likely very costly. It's highly unlikely to be a simple "bolt-in" swap. You'd likely need significant fabrication, custom parts, and likely a significant amount of electrical work to make it function. It's probably a more sensible approach to find a used 318 that's closer to the original engine in your 1984 truck.
