if you see oil concentrating around the area where distributor meets the valve cover, then it is possible that the leak comes from the distributor.
To check, remove the distributor cover and see if there is evidence of oil or burnt oil.
If yes, then remove the entire distributor and check the O ring.
It's quite likely that the O ring is worn out or hardened , which results in the leak.
A drippy distributor will result in hard starts and poor ignition firing and in the long run, high fuel consumption.
I had a similar problem. Replaced the distributor and by chance, saw that the O ring had worn out.
After that, no more leak.
Also check the engine cover (near the distributor) for RTV that may have been dislodged and caused a gap where the oil will flow out.
Another check is the engine cover seal (shaped like the outline of the engine cover.. as mentioned below). If it's hardened, then time to change it.
Hope it helps.