Car engine weights vary significantly, but as of 2015, a 3-cylinder can weigh just over 200 pounds, while a larger V-8 truck engine can weight 750 pounds or more. The steel construction of engines, however, means that they're still one of the heaviest parts of cars.
A car's weight can have a significant impact on its performance and gas mileage, and advanced fabrication techniques allow companies to create durable engines that weigh less than similarly powered engines made during the 20th century. In addition, small economy cars are able to provide better performance without using larger engines than those used previously. Typical small cars generally offer more than 100 horsepower, while models in the 1970s and 1980s might offer 70 horsepower or less.