Why does the Piper Cherokee (PA-28-140) engine have such low horsepower despite the very large displacement?
Aviation engines run at near max RPM through out the flight. A car on the other hand doesn't use the full RPM spectrum except in bursts.1

If a car engine was utilized the same way an aviation engine is, it won't last long.

So an aviation engine is sturdier, heavier, and weaker (hp) for the same displacement, but also provides higher torque (big cylinders).2

Formula One engines have small displacement, very light weight, yet deliver near a 1,000 hp. But they don't last long either. Something like 15 hours of racing and practice sessions.

Further reading: Do Car Engines Make Good Airplane Engines?



1 Piston planes run at near max RPM because they don't have and don't need gearboxes.

2 Same era alloys and technology.