I've been trying set initial spark timing with an MSD 6AL box installed. Instead of getting a single timing mark, I get what looks more like a step ladder with 4 marks. I've checked my timing light on other engines and its fine. I've had another light on it and had the same results.

Someone mentioned to me that this is normal, as the MSD box is discharging multiple sparks hence M.S.D.

If this is true, which mark do I use?

or

Is there a way to get a single spark/mark for this purpose?

Thanks