[Tarrytown SS427s]

I used to classify cars like the black one from SS427's by calling them 427 SS cars..but that just confused everybody. So now I call them Z24 cars and non Z24 cars.

The SS427 option was merely a trim package, just like a Judge, RS, SS396, etc. It was a separate option costing about $95.00 and got you the special trim, bright engine accents, F40 suspension, redlines(or white), and automatically equipped the car with a 427. By the body numbers it wasn't technically ever it's own "model", but in the literature it is classified as such, the same way a regular Super Sport was in 68.