Capable of 1.04 hp/cu. in., the 3350 cylinder has very thin corrugated sheet aluminum stuffed between the usual cast cooling fins to increase surface area. By contrast, a 180-hp O-360 Lycoming makes about 0.50 hp/cu. in. and doesn't come close in sophistication or ability to shed waste heat as the old radials.

https://www.kitplanes.com/engine-theory-engine-cooling-avoiding-meltdown/