I worked on a 305 from around 90 the timing tab was on the cover but it was the wrong cover. the tab should have been on top dead center. He had a short water pump on the engine and I had no idea what was going on. The damper wanted to be almost top before it would run right. Did research and found the right cover and put on a long water pump THEN we could time it by looking down between pump and cover. If nothing else he could time it with a vac. gauge.