Final answer:
In the late 1970s, American cars were known for being less reliable and more expensive 'gas-guzzlers'. The oil crisis led to a consumer preference shift towards more fuel-efficient Japanese cars, contributing to the financial difficulties American automakers faced. Environmental regulations further changed the car market, as emissions standards forced manufacturers to include catalytic converters and produce cars that used unleaded gasoline.
Step-by-step explanation:
American cars in the late 1970s underwent significant changes largely due to the energy crisis during that era. In comparison to their 1950s and 1960s predecessors, 1970s American cars were often less reliable and more expensive. They were typically large, with powerful engines that consumed a lot of gasoline - making them known as gas-guzzlers. The oil crisis of the 1970s and the surging prices of gasoline prompted a shift in consumer preferences towards smaller, more fuel-efficient vehicles.
In response to this shift and the increased competition from Japanese automakers like Honda and Toyota, American manufacturers began to produce cars with smaller engines and lighter chassis. Despite these efforts, Japanese cars, which had been fine-tuned over years of manufacturing small, reliable, and affordable vehicles, grew in popularity in the United States. American automakers struggled to compete, with some like Chrysler requiring federal bailouts to avoid bankruptcy.
Legislation such as the Clean Air Act of 1970 also impacted American cars by requiring reductions in vehicle emissions, leading to the inclusion of devices like catalytic converters in new cars. This necessity for more environmentally friendly vehicles somewhat changed the traditional American automobile's reputation for high performance and contributed to the decline of the muscle-car era.