It's all in how you rate your engine. Comparing car engines to aircraft engines is apples to oranges since they are not rated the same way. An aviation engine

It's all in how you rate your engine. Comparing car engines to aircraft engines is apples to oranges since they are not rated the same way. An aviation engines leaves a decent amount of power on the table in order to be able to claim near continuous duty cycle . Look at their power outputs. They're abysmal compared to similar displacement automotive engines (for something using 100 octane) by the standards of the time they were designed because they are designed for continuous duty If car engines didn't care so much about max power they'd have a higher duty cycle at max power or conversely if aircraft engines cared more about max power it would be easy to make them output greater peak power at which they can't live almost indefinitely. The heavy equipment section of your local craigslist is littered with stuff powered by boring old automotive engines that are rated at a power output (slightly lower than what they would be rated at in cars/trucks) and given sufficient cooling to run indefinitely at that output.