Anybody have a diagram or know where exactly to make these holes? It looks like they could be made in either case half in a flat just below cam level or maybe in the right case half just above the cam.
from Lycoming flyer:
In addition to the inverted oil system, Lycoming makes other engine modifications to adapt standard engine models to aerobatic use. .... Also the flow of oil to the oil pickup in the accessory case is limited in the inverted position. To improve this oil flow, holes are machined in the upper rear wall of the crankcase.