General Motors had discovered back in the late 50s that to stay number one they would have to redesign their cars every two years. The ’63 models from Chevrolet took the market by storm and everyone from Corvette to Impala had new lines and new features. Chevy’s Impala was now a full grown luxury car. But it started out as an upgrade to the Bel Air in 1958 and it had now become one of the world’s finest automobiles. Chevrolet was the world’s largest automobile company and they spared nothing to make the Impala into the most popular, best selling car in America.
The exception was the Z24 option package available in combination with the standard Z03 Super Sport package. Starting in 1967, through 1969, buyers of Z24s Impalas got cars badged as "SS427" models. The SS427 included heavy duty suspension and other performance goodies, as well as a Turbo-Jet 427 in either L36 or L72 variations. Special SS427 badging inside and out were the rule, but few were sold, since "muscle car" enthusiasts were looking toward big-block intermediates like the Chevelle SS396 and Plymouth Hemi Roadrunners, which were lighter and subsequently faster off the line. Interestingly, Z24 cars could be ordered without the Z03 SS package, which meant SS427 equipment but no bucket seats or center console!
