After I copied all cars specifications from Edmunds into Excel format (you can buy full Excel database: Year-Make-Model-Trim-Specs) I analyzed data to show how American cars evolved over past 30 years. I calculated using AVERAGEIFS formulas, breakdown by domestic and imported car model trims available for sale, NOT based on number of cars sold, low-production high-powered cars inflated horsepower figures.
The average engine size rose from 3.33 L in 1990 to 4.09 L in 2007 then dropped to 3.42 L in 2022 due to introduction of turbochargers that allowed downsizing engines, meantime horsepower rose from 142 HP in 1990 to 313 HP in 2022. In 2022 domestic cars averaged 336 HP vs imported cars 295 HP. Cars also grew in terms of external dimensions, but the increase in weight was most significant because more and more SUV models came on market, which also need more power. US manufacturers discontinued many car models in 2020 to focus on SUV, causing a sharp increase in average height and weight and a sharp decrease in average MPG.
Charts based on 1 October 2022 update with 67032 cars (model trims).
Before current upward trend, there was a downward trend from mid-1970s to mid-1980 when most American domestic cars were reduced in dimensions and engine size (and possible horsepower was also reduced at smaller extent) because of 1973 and 1979 oil crisis. For same reason, imported cars gained marketshare (smaller and higher fuel efficiency). Before 1970s even if the number of distinct imported models was similar with number of distinct domestic models, 90% of cars sold in US were domestic made.
Edmunds show car specifications starting from 1990. Where I can find a complete list of older cars with their specifications to analyze them?