Just my .02 cents worth here . . . In the 1950's, Zora Duntov, from Chevrolet, was quoted as saying "We have Sports Cars and we have Super Sports Cars . . ." He was talking about the Corvette SS show car at the time, but later the name Super Sport, became an option on just about every Chevrolet model in the 60's except the Corvette.
A lot of the COPO cars have been tagged as just that . . . A Super Sports Car or "SuperCar" for short. Not all COPO cars are Supercars . . . Remember, a COPO option was also police cars, taxi's, special painted cars or trucks, etc,; and some COPO options included weird options like spoilers, suspension pieces, trim items, etc. So, all COPOs are not Supercars.
But, the COPO options that included the Engine Options in conjunction with other special performance parts from the GM Parts Bins, are generally considered the "Supercars". Does that mean that a L78 Camaro or Chevelle isn't a Supercar, not really, but giving these special COPO cars a name wasn't easy, but like Zora said . . . there are Sports Cars, and then there are Super Sports Cars.
The SuperCar name seems to fit the best for these COPO cars, because they are one notch above the rest of the Super Sports in their given class of cars, either Camaro, Chevelle, Nova, etc. The SS models were the bad boys from Chevrolet, and the COPO High Performance Engine cars took it to the next level . . . thus the name Supercar . . .
By the way . . . as far as I can tell, this web site doesn't cater to only COPO cars. This web site caters to all Chevrolet High Performance Cars . . . and a big
to the Clarys for their true devotion to these cars and this site . . .