This is only marginally on topic, but given the expertise on this list I thought I'd try it here.

A debate rages in my flying club (a Skyhawk, Superhawks and a Cardinal RG) about how much oil to keep in the planes.  The POHs say a MINIMUM of 6 quarts.  Some members say anything over 6 is blown out on the belly.  At least one of the Lycoming manuals says the minimum for safe operation is 2 quarts!

Recognizing that the POH is "the law," is there any risk to engine life running below 6 quarts?  What is the "optimal" amount for engine cooling?