* Vehicle configuration: Is it a dually (dual rear wheels)? A single rear wheel? What is the overall weight (GVWR)? Different configurations impact fuel efficiency significantly.
* Driving style: Aggressive acceleration and high speeds drastically reduce fuel economy.
* Maintenance: Properly maintained vehicles tend to get better gas mileage.
* Terrain: Driving in mountainous areas or off-road will lower fuel economy.
* Load: Hauling heavy loads will dramatically reduce gas mileage.
Therefore, there's no single answer. You won't find a precise EPA estimate for this truck because those numbers are typically given for lighter-duty vehicles. Expect very low gas mileage, likely in the range of 8-12 MPG in most situations. It could be lower if you frequently tow heavy loads or drive aggressively. Anything higher would be considered exceptionally good.
To get a better idea of the fuel economy for a *specific* 1994 Chevrolet 3500 454, you'd have to find information specific to that truck, such as previous owner logs, or monitor your own fuel consumption.
