Cusser
+1y
Mine's set at factory 6 degrees BTDC at idle, and I loosen the AC belt and let it hang down for a better view of the timing mark on the timing cover (paint those white, too).
Most engines can handle like 30 degrees TOTAL advance, that's like at 3500 rpm. So you'd have to either have a fancy timing light or mark the pulley to do it that way. I was suggesting to set up a standard timing light and revving the engine, and see if the mark actually advances. It likely will, but then you'd know. Failure to advance can be bad vacuum hose, bad advance "can" on distributor, or carb not pulling a vacuum from that port. Tee-ing in a vacuum gauge temporarily can help determine.