* Some versions were: Galaxie 500s equipped with high-performance big-block V8 engines (like the 427 or 428) and specific performance options certainly qualify as muscle cars. These were often marketed as high-performance models within the Galaxie lineup. Think of the XL or the R-code models.
* Many were not: Many Galaxie 500s were equipped with smaller, less powerful engines and focused more on luxury and comfort. These would not be considered muscle cars.
The key difference lies in the emphasis. Muscle cars prioritized performance above all else, usually in a relatively affordable package. While high-performance Galaxie 500s offered impressive power, the overall size and luxury features blur the lines sometimes. They were powerful, but some lacked the nimbleness and affordability typically associated with muscle cars.
