* Small-block V8s: These were likely the 5.0L (305 cubic inch) and the 5.7L (350 cubic inch) versions. The exact horsepower ratings varied slightly depending on the carburetion and other factors.
* A few models might have offered the 4.3L V6: This was a less common option, but not unheard of in that year.
It's impossible to say definitively *which* engines were available without knowing the precise model and trim level of the specific 1984 Chevrolet van. A vehicle identification number (VIN) would be needed for that level of detail.