* Engine size: Larger engines often came with taller (numerically lower) gear ratios for highway cruising, while smaller engines might have had lower (numerically higher) gears for better acceleration.
* Transmission type: Automatic transmissions often paired with taller ratios than manuals.
* Intended use: Trucks ordered for towing or heavy-duty work might have had lower gear ratios.
* Specific options: The buyer could often specify the rear end ratio as part of the order.
To find the original ratio for a *specific* 1978 Chevy Silverado, you'd need to check the vehicle's original build sheet (if it exists), the data plate (often found on the driver's side doorjamb), or the owner's manual. The axle code on the data plate might provide a clue, but you'd need a decoding chart for that year's model.
