* Trim level: SS models, particularly 454 SS versions, are far rarer than base models or intermediate trims like Malibu. Convertibles are also less common than coupes or sedans.
* Options: Specific options packages and individual options (like engines, transmissions, interiors, and paint colors) dramatically affect rarity. A car with a rare combination of options will be much rarer than one with common options.
* Condition: The condition of the car plays a huge role. A fully restored, numbers-matching example is far rarer (and more valuable) than a rusty project car.
* Survival rate: Many Chevelles from 1971 have been lost to time due to accidents, rust, or neglect. Simply existing makes a car somewhat rare.
Therefore, there isn't a single answer to how rare a 1971 Chevy Chevelle is. A common Malibu sedan in average condition is relatively common, while a concours-condition LS6 Chevelle SS convertible is incredibly rare and highly valuable. You'd need to specify the trim level, options, and condition to even begin to estimate its rarity.
