the LS6 SS454 Chevelle was bought just as the owner got appointed to be an FBI agent

and to prevent his irrational and cranky boss (J Edgar Hoover) from getting bent out of shape, he had the dealership paint over the white hood and trunk stripes

While sitting on the dealership lot, the carb, air cleaner, and battery were stolen, so -  the dealership put aftermarket parts on to keep it running.

Because of both factors, cranky boss, and theft target, the buyer also had the dealership replace the 454 badges with 350s.

So, this car came from the factory as an all black 350 SS LS6

Full story at https://www.hotrod.com/articles/not-even-fbi-knew-secret-identity-1970-chevrolet-chevelle-ss454-ls6