Engine configuration

Greetings!

My last post provoked a long and interesting series of threads so I am
emboldened to make another post.

This question concerns the configuration or layout of an engine. I have
noticed that air-cooled engines tend to have an opposed configuration
whereas liquid-cooled engines tend to have a V configuration. Both are
also available inline but I'll take a leap and say these are a minority
(I'm talking about current production engines not historical engines).
There are some liquid-cooled horizontally-opposed engines but I can't
think of any air-cooled "V" engines. Why is this? It suggests to me that
the advantages of the V configuration are specific to liquid cooling. Is
this really the case?

The Wikipedia article on "V Engine" is quite short but it includes this:

"Certain types of V engine have been built as inverted engines,
most commonly for aircraft. Advantages include better visibility
in a single-engined airplane, and lower centre of gravity."

OK, these are two pretty good advantages! There are no disadvantages
listed. So why isn't the Lycoming O-540 or the Continental O-520 an
inverted V?

Regards,

Michael