In article Udl2f.419464$_o.299013@attbi_s71,
says...
Seems anything above 6 1/2 it just leaves...

Yep, we always kept 6 quarts in our O-320-powered Warrior. Anything above
that just blew overboard.

We kept 8 quarts in O-360-powered Archers, for the same reasons.

And we now keep 9-10 quarts in our O-540-powered Pathfinder.

Of course, now we have an air/oil separator, so we *could* keep 12 quarts in
it...

You *will* keep 12 quarts in it - after you've experienced a serious oil
leak in flight.

--
Duncan