The Corvette was born in an era of automobile manufacturing we can hardly recognize today; though the moving assembly line has been a part of production car building since the days of the Model T, five decades later when the Corvette was introduced for the 1953 model year, the process was still pretty similar, with human hands involved in every step. Though the only options available for those Year One Corvettes were a heater and AM radio (and every one of the 300 cars produced came with both options!), by the end of the C1 generation the list of options had swelled to nearly 20 different choices, and it continued to expand through mid-year and C3 production.
One particular option that spawned numerous variations was the rear axle gear ratio and differential type, with both open and Positraction diffs offered over the years and gear sets for manual transmission, automatic, and performance-oriented use thrown in the mix as well. For some Corvette owners, determining the right axle combination to match their car’s configuration as-manufactured is a concern, while others might want to find a factory option that’s period-correct for their car but offers better performance than what it came with.
Once again when it comes to matters of classic Corvette technical knowledge, Corvette Central’s CC Tech website comes to the rescue, with a very informative article that describes how to empirically determine your gear ratio by measuring driveshaft rotation, then takes you through axle options year by year. It’s a useful resource whether you’re looking to put things back to factory, or put some extra pep into your ‘Vette with an OEM option swap.