360 LA getting oil in #3 cylinder.

Personally, I'd start by pulling a valve cover and then roll the motor over by hand. Make sure all the valves open in the proper sequence.
I've seen engines lose an intake rocker or lose an intake lobe and oil gets sucked up past the rings.
It's a longshot, but you'd also get a chance to see inside the engine and valve covers for oddities.
The only time I've seen that much oil in an engine was when my sister put 12qts in her Nissan pulsar, capacity was 3.5...
It was blowing oil out the breather into the air cleaner..
Can you post a picture of under the hood? Show where things are routed and connected? Might not be a bad idea to check the oil level, or even drain and refill.