The weight of a 1984 Chevy K-20 truck varied depending on the specific configuration (cab style, engine, options, etc.). There's no single answer. However, a reasonable estimate for a standard 1984 Chevy K-20 would be
between 4,500 and 5,500 pounds (approximately 2,041 to 2,495 kg).
To get a more precise weight for a particular truck, you would need its specific specifications from its original documentation or a vehicle identification number (VIN) lookup.