340 Rear Main Seal and/or Oil Pan leak

Bad Sport said
I've driven cars in the past with worse leaks than that, as long as the oil level is good, it shouldn't hurt anything, other than make a mess.

Have you by chance checked for a leak up around the oil pressure sending unit back of engine right on top?

Sorry, forgot to mention that. I have checked the top back on the engine: oil pressure sender, valve covers and intake. No leaks from the top. I can deal with the oil mess until it's fixed.