[tdangle]

Easy, with the engine idling (not in gear) lower the speed as much as you can. Note the timing it's currently at. Now slowly raise the engine speed watching the RPM and keeping the timing light watching the timing. As soon as it starts to advance that the where your timing starts advancing. Using a dial back timing light you can map out your total advance and when it happens. Don't forget to disconnect the vacuum advance with doing this as you want to see true initial and mechanical advance. At idle you can hook up the vacuum advance to manifold vacuum and measure the total vacuum advance you get. If you have a hand vacuum pump you can also see when it starts and total amount. Have fun.