hi everyone

I have an 12 year old 306 that keeps dropping a cylinder or 2 at random.
there is a little bit of oil collecting on the top of one of the spark plugs above the threads which makes me think the head is cracked, i cant see any oil leaking from any were else that could the build up there. The oil is dropping but very slowly over a couple of months.

I have replaced the spark plugs, but nothing else.

does this sound right and if so anybody want to buy a 306 off me? lol

thank you