Received the case replacement today... Narrow to wide... I had one question? I was expecting a -36A or 51A... When I seen the -27A, I knew this was from a O-320-E2D, normally this would have the small or narrow front main bearing. But as I looked the case was configured for the long one piece bearing. I called Chuck Ney in Tulsa... He was really nice to explain all the mods / upgrades to the case.
Long story short... the O-320/360 are poured with the same casting 72081/2, and what determines the - dash number is how it is machine. Chuck has been doing these cases for years, and was one the first to get approval to rework these cases back in 1970... Really knows everything about lycoming and as you can see owns a few STC's... So, the case has been updated and machined as 0-360 (-36A).