* Transmission type: Was it a 3-speed manual, a 4-speed manual (possibly a Spicer), or an automatic (likely a Powerglide or possibly a Turbo-Hydramatic, depending on the year and options)? The transmission itself had different gear ratios.
* Axle ratio: This is stamped on a tag usually located on the differential housing. Common axle ratios for a 1-ton in that era ranged from 4.10:1 to 5.13:1, but others existed. This is the *most* crucial piece of information.
Where to find the information:
1. Differential tag: Look for a metal tag on the rear differential housing. This will have the axle ratio stamped on it (e.g., 4.10, 4.56, 5.13).
2. Owner's manual (if you have it): The original owner's manual might list the gear ratios for your specific truck's configuration.
3. Build sheet (if you can find it): A build sheet (if it survives) from the factory will specify the options and components, including transmission and axle ratio.
4. Vehicle Identification Number (VIN) decode: Decoding the VIN might give you some clues, but it won't always specify the axle ratio. Online VIN decoders can help, but results are not always definitive on this level of detail.
Without knowing your specific transmission and axle ratio, it's impossible to provide the correct gear ratios. Once you find the axle ratio on the differential, you can search online for common transmission gear ratios for Chevy trucks from that era and the specific transmission type installed.
