Oil leak under high pressure?
We had snow Thursday. Now it's just 35°. yay. You have two main oil galley pipe plugs in the rear of the block. If your car is sitting motionless, there is very little pressure forcing oil out the rear main, unless you have a lot of crankcase pressure. I would try pulling the breather/PCV, and do it again several times over the course of an hour. If it slows down, its either the gasket or seal. If it keeps doing it, it's very possible its te oil galley plug(s) and/or cam plug.