problem
M104 heads, M119 valve covers, M113 oil-cooler seals that impersonate a rear-main leak.
Head gasket at the back of the head, plus valve-cover gaskets raining onto the harness. A misting 320 is not dying; a creamy coolant reservoir is.
Valve covers, front timing cover, pan. The engine is internally tough. It just does not like to keep its oil a secret.
The oil-cooler seals at the filter housing dump down the back of the engine. It looks exactly like a rear-main leak from above. Check here first.