Supermouse3: It is strange they aren't intercooled and liquid cooled, simply cannot build a properly efficient engine that isn't liquid cooled, doesn't matter how many sensors or computers you throw at an IO-540, it's never going to be anywhere close to a car engine
Are you sure? Have you compared the BSFC of an air cooled aircraft engine to an automobile engine?
You might be surprised how close the two are. The old Lycoming/Continental lumps may be pretty long in the tooth but they measure up pretty well against the new fangled, computer controlled, liquid cooled, automotive engines.