By the 1970s, emissions and safety regulations, along with soaring gasoline prices and an economic downturn, meant demand dropped for all muscle-type models. As with other American vehicles of the time, there was a progressive decrease in the Barracuda's performance. To meet increasingly stringent safety and exhaust emission regulations, big-block engine options were discontinued. The remaining engines were detuned year by year to reduce exhaust emissions, which also reduced their power output. There was also an increase in weight as bumpers became larger and, starting in 1970, E-body doors were equipped with heavy steel side-impact protection beams. Higher fuel prices and performance-car insurance surcharges deterred many buyers as the interest in high-performance cars waned. Sales of pony cars were on the decline. Sales had dropped dramatically after 1970, and while 1973 showed a sales uptick, Barracuda production ended 1 April 1974, ten years to the day after it had begun.