Superbird: the other teams got butthurt and made NASCAR change the rules.
wiki:
https://en.wikipedia.org/wiki/Plymouth_Superbird
NASCAR's rules implemented for the 1971 season limited the "aero-cars" to an engine displacement of no greater than 305 cu in (5.00 l) or they had to carry much more weight compared to their competitors. While they were still legal to race, the power-to-weight consequences that would come with the smaller engine or the increased weight rendered the cars uncompetitive. This was the start of a trend of rules slowing down NASCAR, because the races were exceeding the technology of tires and safety over 200 mph (320 km/h).
Still garish garnish on a brick.